minor: fixing misleading code comment in bson_ext
Raise error on insert into system collection.

Only if the collection is not system.users or system.indexes.

[ RUBY-492 ]
RUBY-475 refactor read preference logic

Move read_pool into Mongo::ReadPreference
Add #read_preference to produce read preference hash
RUBY-475 pin/unpin logic added to cursor
minor: moving away from .rvmrc, adding gitignore for .ruby-version
minor: merge should be called with parens here
RUBY-537 fixing behavior of strict, adding deprecation notice
improvement: limiting db#command calls for capped?, cleaning up init
improvement: clean-up of db, lots-o-improvements
Merge pull request #176 from mongodb/raise-error-on-system-insert

Raise error on insert into system collection.
Reverting the collection name check on insert.

[ RUBY-492 ]
RELEASE 1.8.4.rc0
minor: adding license to gemspecs to get rid of warning
RUBY-567 cast VALUE to char * to avoid warning
minor: removing rvm gem, package task can't be automagic anymore since we combined bson.gemspec
minor: fixing deprecation notice in the docs
minor: changes to deploy rake tasks
RELEASE 1.8.4
minor: more fixes to deploy scripts
minor: remove puts