plugins: remove plugin types not available in current version
update 2012 cmd caches (mostly, for proper 0-arg bool flag handling, for mel2py)
melscan: commented out element_list rule, not used
melparse: if errors while parsing, raise an error - don't silently translate only a portion!
melparse: fix handling of array initialization, add matrix handling
melparse: make formatting of do-while loop avoid copy/paste of entire loop body
melparse: cleanup handling of callback-formatting
fixed bug if callback text ended with a space - ie:
    button -c "myCmd; "
made sure that all "pieces" of callback are executed
   ie, previously, this mel:
       button -c "cmd1; cmd2"
   would be translated as:
       button(c=lambda *args: cmd1() and cmd2())
   ...which meant that if cmd1() returned False, cmd2() was never run
   now, it is translated as:
       button(c=lambda *args: [cmd1(), cmd2()])
melparse: better formatting of flags in unknown mel commands
melparse: fix storing of line-numbers in token-slices
mellex: fix line-numbers with block-comments
melparse: make more pep8-ish
melparse: fix for default string value
melparse: pep8 - spaces around equals in assignment
melparse: when verbosity 2 or greater, assemble prints more info
melparse: pep8 - eliminate some spaces inside parentheses
melparse: code reorganization
melparse: make sure a 'pass' statement is inserted where required
melparse: fix switch statement when there is only a default case, or when a case only has comment lines
melparse: proper checking if command name defined in current module
melparse: turn block comments before a func into the func docstring; fix block comment indentation