Add some logging to Parser

Also, fix a couple of warnings.
Halt execution in IF instead of ID

This will avoid the creation of ghost instructions in the pipeline. Fixes #50.
Check also ID and EX for emptiness before halting

Also, add some logging messages and change == to equals().
Add failure messages for FPU forwarding tests
Add parentheses around the instruction name

Useful to detect instructions that have " " as a name during debugging.
Fix lint warnings in CPU.java
Fix lint warnings in SYSCALL.java
Fix some lint warnings in Main.java
Fix lint warnings in Instruction.java
Fix lint warnings in CpuTests.java