Implemented non editable expression statement
Added minus prefix
Simplified the names of classes
Massive renaming to simplify class structure
Restructured packages
More naming refactoring and clearification of packet structure
Adjustments to the grammar to support the new datatypes
Not and Minus expressions do now validate their types as well
Included line numbers for better error handling
Grater than and equal than introduction
Multiple prefixes == no problemo
Adopted grammar to support multiple prefixes
Merge branch 'master' of github.com:software-engineering-amsterdam/poly-ql