Update Constants - add GIGA and use hardcoded PI. [Core]
Merge branch 'v0.8'

Conflicts:
	jlinda-core/src/main/java/org/jlinda/core/Constants.java
Finalized InSAR Coregistration Help. [CoregHelp]

 Entries for:
   - tutorial on InSAR coregistration
   - Create InSAR Stack
   - Coarse Fine Coregistration
   - CPM Estimation and Resampling
Finalized Help for Cross InSAR Resampling. [CrossHelp]
Unwrapper implementation selected based on platform and arch. [Unwrap]

  Native or Java code selected based on platform and architecture.

  Interface to GLPK library works, and bee extensively tested on
  Linux64 and this the only platform supported at the moment.
  For other platforms and architecture the operator will default to
  to the Java unwrapper implementation.
Finalized Help for Unwrap fumctionality. [UnwHelp]

 - Entries for Unwrap and Stitch operator.
Add entries for Coreg, Cross, Unwrap to help toc. [Help]
Update version to 0.8.

Closes: #8, #11, #12