added *.pdf and *.synctex.gz to gitignore

Conflicts:
	.gitignore
added spec latex documents to gitignore

Conflicts:
	.gitignore
quantity units are now output as an attribute rather than a separate tag
added PATH search for nrnivmodl
changed xmlns default
Refactored all port objects and validators to explicit port names, e.g.
AnalogPort(mode="send") to AnalogSendPort etc
removed unneeded "port-factory" code to generate ports. Refactored
test_AL_API.py but not sure if it still works properly
Tested and debugged ports changes
Capitalised element names
Converted parameters to properties
added missed Parameter->Property conversion
Capitalized Quantity and Value
Added Reference UL object and changed Value->scalar/random_distribution
to Quantity->Value/Component>RandomDistribution etc...
Merge pull request #9 from tclose/new_version1_syntax

Switched Ports from AnalogPort/EventPort to AnalogSendPort/AnalogReceivePort/EvenSendPort/etc...