PgSqlDriver: fixed reflection for tables with the same name across the schemas

Construct ::regclass ensures selection of table in respect to 'search_path' setting.
PgSqlDriver: getForeignKeys() returns FKs from current schemas only
PgSqlDriver: reflection supports table in FQN
Merge pull request #18 from milo/pull-pg-reflection

PgSqlDriver reflection fixes
SqlBuilder: added support for NOT with NULL
Merge pull request #20 from dg/pull-null

SqlBuilder: added support for NOT with NULL
tests: added test for IN
SqlPreprocessor: added support for '.' in column names
SqlPreprocessor: added support for operator in WHERE & AND
Merge pull request #22 from dg/pull-operator

SqlPreprocessor: added support for operators inWHERE
PgSqlDriver: removed unnecessary closure
Postgre driver: added support for returning FQN table names [refs #17]
SqlBuilder: constructor requires Context (BC break!)
Structure: non schemed table names are resolved as FQ table names
DiscoveredConventions: fixed support for schemed FQ table names
tests: added tests for schemed FQ table names
SqlBuilder: fixed support for schemed FQ table names
Merge pull request #24 from hrach/schema

Implemented support for schema [closes #17]
.travis: added code checker
SqlBuilder: added support for parsing self-reference