Move mastercore_/omnicore_ files into subdir

[dexX7]

I suggested this earlier, but @m21's response was something like "this creates trouble for mobile users and there is another reason I can't tell", which left me a bit wondering, and I'm not really sure, what that reason could be, or how this might affect mobile users.

Until now, all files were prefixed with mastercore_, but #13 further introduces omnicore_, and in my opinion this is pretty messy, and I'd really like to move all files into a subdir, and get rid of that prefix.

So:

1. Any objections?
2. What name would you like? src/omnicore?
3. @zathras-crypto: assuming we do this, could you update your pending PRs?

---

For my experimental, modular branch, I have a several layers deep file structure, and aside from the actual content, this is basically were I'm going:

https://github.com/dexX7/bitcoin/tree/experimental-minimal-encoding/src/extensions

---

In particular, I suggest to use a one layer deep structure to at first, because anything else would be an overkill for now, with two exceptions: the tests and the docs (but not the main README.md). The change could look like:

doc/apidocumentation.md                         -> src/omnicore/doc/rpc_api.md // ..?
src/mastercore.cpp                              -> src/omnicore/omnicored.cpp  // ..?
src/mastercore.h                                -> src/omnicore/omnicored.h    // ..?
src/mastercore_convert.cpp                      -> src/omnicore/convert.cpp
src/mastercore_convert.h                        -> src/omnicore/convert.h
src/mastercore_dex.cpp                          -> src/omnicore/dex.cpp
src/mastercore_dex.h                            -> src/omnicore/dex.h
src/mastercore_errors.h                         -> src/omnicore/errors.h
src/mastercore_parse_string.cpp                 -> src/omnicore/parse_string.cpp
src/mastercore_parse_string.h                   -> src/omnicore/parse_string.h
src/mastercore_rpc.cpp                          -> src/omnicore/rpc.cpp
src/mastercore_rpc.h                            -> src/omnicore/rpc.h
src/mastercore_script.cpp                       -> src/omnicore/script.cpp
src/mastercore_script.h                         -> src/omnicore/script.h
src/mastercore_sp.cpp                           -> src/omnicore/sp.cpp
src/mastercore_sp.h                             -> src/omnicore/sp.h
src/mastercore_tx.cpp                           -> src/omnicore/tx.cpp
src/mastercore_tx.h                             -> src/omnicore/tx.h
src/mastercore_version.cpp                      -> src/omnicore/version.cpp
src/mastercore_version.h                        -> src/omnicore/version.h
src/omnicore_createpayload.cpp                  -> src/omnicore/createpayload.cpp
src/omnicore_createpayload.h                    -> src/omnicore/createpayload.h
src/omnicore_encoding.cpp                       -> src/omnicore/encoding.cpp
src/omnicore_encoding.h                         -> src/omnicore/encoding.h
src/omnicore_rpctx.cpp                          -> src/omnicore/rpctx.cpp
src/omnicore_rpctx.h                            -> src/omnicore/rpctx.h
src/omnicore_utils.cpp                          -> src/omnicore/utils.cpp
src/omnicore_utils.h                            -> src/omnicore/utils.h
src/test/mastercore_obfuscation_tests.cpp       -> src/omnicore/test/obfuscation_tests.cpp
src/test/mastercore_rounduint64_tests.cpp       -> src/omnicore/test/rounduint64_tests.cpp
src/test/mastercore_script_dust_tests.cpp       -> src/omnicore/test/script_dust_tests.cpp
src/test/mastercore_script_extraction_tests.cpp -> src/omnicore/test/script_extraction_tests.cpp
src/test/mastercore_script_solver_tests.cpp     -> src/omnicore/test/script_solver_tests.cpp
src/test/mastercore_strtoint64_tests.cpp        -> src/omnicore/test/strtoint64_tests.cpp
src/test/mastercore_swapbyteorder_tests.cpp     -> src/omnicore/test/swapbyteorder_tests.cpp

[m21]

No objections guys.
Can't recall that comment, but you're driving it now and know what you're doing. :)

[dexX7]

Thanks @m21, I really appreciate your input!

[zathras-crypto]

Any objections?

No objections from me either :)

What name would you like? src/omnicore?

Sounds good to me. Out of interest, what about QT stuff?

@zathras-crypto: assuming we do this, could you update your pending PRs?

Of course, no worries :)

[dexX7]

Let's move further discussion to #16.