-Codechange: Access file info through pointers and not indexes

Will be useful in order to reorganize the PAK processing
-Codechange: retrieve data/ content at runtime instead of using static fileinfo table

Only the Linux/Posix code is implemented,
Win32 version has still to be done
-Codechange: read PAK files in an endian agnostic manner
-Codechange: implements ReadDir_ProcessAllFiles() for Win32

Use FindFirstFile() / FindNextFile() / FindClose()
-Fix: Fix coding style issues from previous commits
-Fix: support longer filenames in _File_Init_ProcessPak()

Also return false when the maximum length is reached
-Fix: bug in fread_le_uint32()
Merge pull request #192 from miniupnp/file_open_rework

File open rework