[2.0] More work on ClassmetadataExporter and ConvertMappingTask for converting mapping information between various formats

[2.0] Some work over SchemaTool update of schema (affects directly the CLI schema-tool task on --update option.

[2.0] Refactored classloader architecture. Renamed ClassLoader => GlobalClassLoader. Introduced IsolatedClassLoader that is suitable for participating in autoload stacks. Added 2 example entity classes to the sandbox with 2 xml mappings and 2 yaml mappings. Simplified sandbox setup.

[2.0] Removed xdebug builtin support from Debug::dump(). Added run-dql CLI Task. Updated tasks to wrap Exceptions thrown and diplay nicely. Fixed bug with CLI that ws incorrectly splitting strings into an array instead of consider them raw.

[2.0] Fixed issue with RunSqlTask. Added basic support to --update in SchemaToolTask. Misses some internal implementation

[2.0] Updated description for pear packages. Enhanced ClassLoader to support the old namespace separator (underscore) for Zend/PEAR/... compatibility until some day when they all use 5.3+.

[2.0] Work on CLI: Added SchemaToolTask with preliminary support for dropping/creating the database schema. Prepared the sandbox. Adjusted build to include the sandbox.

[2.0] Implemented base of CLI tasks. Also included drafts of Version and Help tasks. Implemented two Printers: Normal and ANSI Color.

[2.0] Refactored pieces of QueryBuilder, it does not use string concatenation anymore. Splitted from into from and join, allowing update and delete DQLs to be correctly built. Added missing entry set. Removed Expr\Having because it was useless. Updated docs.

[2.0] Applied fixes for character casing issues. Simplified inheritance mapping and improved handling of outer joins in Class Table Inheritance.

[2.0] Removed AssociationMappings from ResultSetMapping  for improved caching. Fixed caching issue with reflection classes and properties. Reimplemented and leaned up broken identifier quoting. Added support for named (native) queries. Fixed small hydration memory leak.