Updates in sys_rsx and CellGcmDisplayInfo

Thanks a lot to @3141card for all the relevant information about RSX
related lv2 syscalls.
cellGcmSys changes and minor fixes
Merge pull request #763 from DHrpcs3/gcm-wip

cellGcmSys and sys_rsx changes
Implemented L10nConvertStr as only char* -> char* (type).
This may be used in other l10n functions, since it was designed to receive void* pointer.
Find sizeof(size_t) is 4 (uint32_t?) in Guided Fate Paradox. Thank @B1ackDaemon for testing.
Changed log content for this function. Also fixed many typos..
Need windows sdk for code page transformation on windows. Need iconv to build on Linux/Mac.
Original source for char to char codepage transformation is already tested using codeblocks and vs.
Noticed l10n_conv_t is omitted in reference, which may be replaced by iconv_t or simply other function.
Modified .travis.yml to apt-get install libc6-dev and removed -liconv from CMakeFile.txt.
Merge pull request #765 from Syphurith/patch-L10nConvertStr-rebuilt

L10nConvertStr
RSXVertexData bugs fixed

* Some extra info on sys_rsx syscalls
* Code cleaned in GLGSRender.cpp
Fragment Shader recompiler comments

Don't expect changes due to this commit.
Vertex Data base offset/index

Fixed incorrect default value in RSXTexture.