Handle change_column error when column has default binding or indexes.

Tests for #455.
these tests were only meant for MS-SQL
Adding recognition of double quote (") as a valid quote delimiter
Renaming def to line up with SQL terminology.
Return early if table name is nil
we should first allow super AbstractAdapter to initialize then extend spec

otherwise using *adapter: jdbc* configuration might no work (fixes #457)
test that we allow `nil` to be passed into `table_exists?` (details at #460)
use the maven released postgresql driver as dependency for IDEs
only add gem jruby-openssl for JRuby < 1.7.0
remove Gemfile.lock from repo
static ALLOCATOR gets final
verified that DATABASE_URL now works as expected (even with JDBC props)

e.g. `rake db:version DATABASE_URL="mysql://localhost/rails32?prepared_statements=true&cachePrepStmts=true&cacheResultSetMetadata=true&profileSQL=true"`
[postgres] hstore values should be returned as Hash instances (fixes #454)
rebuild jar due changes
helper gems should contain all files from lib/* (thanks to @nertzy fix #463)

also reviewed limits impossed on driver versions - esp. for next postgres JDBC we will very likely be fine using 9.3
prepare for releasing 1.3.1
development at 1.3.2.DEV
Correct logic in tasks.rb
Prevent rake from throwing an exception when task w/o comment is redefined
fix rake task name **db:structure:load** (missing db: prefix - closes #465)