VMPC2000XL v0.6.4

• Fix various issues when using more than 127 sounds.
• Implement 256 sounds in memory limit. Before this, VMPC2000XL would allow over 256 sounds in memory at a time, which is incongruent and incompatible with the real MPC2000XL.
• Fix iOS keyboard configuration and learn (i.e. Shift + 0 and then F2 for KEYBRD).
• Fix sound and program name derivation. To summarize, the real MPC2000XL uses the sound or program name that is encoded in the actual the file data -- with mixed casing, like CoolKick or NewPgm-A -- if, and only if, the encoded name is a case-insensitive equivalent of the file name. If it's not, the file name becomes the sound or program name, resulting in upper casing, like COOLKICK or NEWPGM-A. VMPC2000XL now follows this behaviour.
• Minor cosmetic fixes in KEYBRD, Copy Sound, and Channel Settings screens.
• For developers: I'm learning Vim, so I've made some minor changes to facilitate working on VMPC2000XL in Vim. The main change is the creation of compile_commands.json during the CMake generation stage. The rest of my setup can be found here.

A special thank you to all the bug reporters on GitHub!