Add options method, tablespace to create index

Index method and tablespace is very useful.
Add index method (USING btree, for example) and tablespace according to CREATE INDEX expression in postgresql documentation.

http://www.postgresql.org/docs/9.3/static/sql-createindex.html
Update schema.moon
Merge pull request #83 from dant4z/patch-1

Add index method and tablespace to create index
add where option to include_in
make Model\extend take raw table name, rebuild
convert more lua examples
move default_environment, add run_with_server
copy constraints over to class when using extend helper
more lua translations
assert error passes through all arguments
use defaut_environment method
convert more docs to lua
more database doc updates for lua
moving more reference around
model\find_all supports where option
docs for find_all arguments
time ago supports times in the future
escape_identifier is aware of db.raw
extract options does not consider raw values
gen_index_name is aware of raw, add specs