cache describe during request
ensures username is updated on a username/password update for a project refs joeferraro/MavensMate#214
describe_data cache var
respect mm_ignore_managed_metadata on folder-based metadata as well
split symbol table indexing into requests of 20 Apex classes at a time should fix the issue where the tooling endpoint gacks

refs joeferraro/MavensMate#200, refs
joeferraro/MavensMate-SublimeText#309