Implemented more features of the Quake map parser

- Add single float min/max constructor to BBox
- Let MapParser create the map instead of passing it in
- Minor fix in Parser
- Parse entities and entity keys in Quake map parser
- Make Token typedef public in Tokenizer
- Add hasProperty() method to Entity
- Default to empty string for the default value when getting an entity property
- Add set(float) method to Vec template
- Added some test cases to VecTest
- Added QuakeMapParserTest

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>