Remove deprecated AbstractSchemaManager::getFilterSchemaAssetsExpression(), Configuration::getFilterSchemaAssetsExpression() and Configuration::getFilterSchemaAssetsExpression()

Reworked type-based and conditions and clarified some types to justify the ones that remain unchanged.

Change "we're" to "where" in docblock for listTableColumns()
method. Add comma to improve readability.

Inherit table charset/collation from db charset

This coherent with what is done for Table. All platform specific things
are grouped into an options array. Eventually flags should be migrated
into options as well.

Support for Partial Indexes was available in Doctrine 1 following
http://www.doctrine-project.org/jira/browse/DC-82. This commit
reintroduce support for Doctrine 2. We use the same syntax with an
optionnal "where" attribute for Index and UniqueConstraint.

- Fixed docblocks
- Removed return statements on void methods
- Cleaned up unused private / local variables
- Fixed license issues
- Removed SVN leftovers
- Fixed doctrine-project.org links
- Added line breaks before return statements