Setup basic code to test Vhdl Parsing. Low level APIs were tried out.
Added commands display_entities and import_vhdl. Also changed the structure of vhdl conversion.
Merge branch 'master' into Low_Level_Vhdl_Parsing_Feature
Added parameters for new_entity command. Added test for connection between entities. Add Entity simulator and Project simulator.
Implemented parentChild and childParent connections. Added EntityConnectionManager and ProjectConnectionManager.  Added closeProject command.
Added new_and_gate command
Added basic code to read vhdl file and convert it to Progen. Also added basic code to convert from Progen to VHDL
Removing VMagicProgenConverter.java because contents have been moved to VhdlToElectronicsConverter
Made addInput, addOutput and addChildEntity of Entity public to support entity addition from outside of project
Changed parent id of entity to a reference to parent entity. Also refactored the Entity's connection manager update to take place through projectConnectionManager itself.
Fixed null pointer exception in DisplayAllEntities
Remove unused import for bean shell
Added basic setup code for processing basic connections
Merge branch 'Low_Level_Vhdl_Parsing_Feature' of https://github.com/DineshThangavel/Progen into Low_Level_Vhdl_Parsing_Feature
Added new entities like flip-flop, further developed parsing of VHDL
- simulation of AND and OR gate work individually
- added SignalBusObserver, AddInputStimulusCommand,  ChangeInputSimulatorValueCommand, StartSimulationCommand
- Refactored AND gate and added OR gate commands
- Added test for verifying the simulation of AND, OR gates
Fixed some bugs to support simulation of multiple connected entities. Added a test verifying the same.
Added register entity and support for simulation of clocked devices like registers.
Added ConnectToClockCommand, newRegiserCommand
Added test for simulating the functionality of register
Added support for child entities simulation. Also added export to VHDL command
Support Multiplexer entity #2

- Added newMulitplexerCommand, new multiplexer entity, test for simulating multiplexer