Added local variable support, almost completely implemented.
classfile_writer: now using method to determine number of local vars.
bytecode_generator: implemented variable_push/pop. Referring to local_variable_stash to determine local var count.
local_variable_stash: Holds a map of strings (var names) to index (in var table of method).
Merge branch 'master' of https://github.com/ccebinger/SWPSoSe14