Update for Csound 6.16.0

[nwhetsell]

This pull request updates built-ins for Csound 6.16.0.

[Anteru]

This also removes a few built-ins -- is this by design? If someone tries to highlight older Csound files they won't get them highlighted, so I wonder if it might be better to move them into some deprecated token type etc. instead.

[nwhetsell]

In 69e5a01, I added a set of REMOVED_OPCODES so that removed built-ins are highlighted in older Csound files. REMOVED_OPCODES contains the 25 built-ins that have been removed since Csound was added to Pygments (727e014):

• 32c622b: sumTableFilter, systime, vbap1move (3 built-ins removed)
• 5ec2eb9: OSCsendA (1)
• 9f33ecb: pvsgendy, socksend_k (2)
• 9ad41d6: buchla, mp3scal_check, mp3scal_load, mp3scal_load2, mp3scal_play, mp3scal_play2, signalflowgraph (7)
• d3edab1: beadsynt, beosc, getrowlin, lua_exec, lua_iaopcall, lua_iaopcall_off, lua_ikopcall, lua_ikopcall_off, lua_iopcall, lua_iopcall_off, lua_opdef, tabrowlin (12)

[Anteru]

Merged, thanks!