Allow specifying android ndk to use at command line

Documentation indicates that the path to the ndk to
use to build could be specified at the command line
except whenever 2 arguments were specified for 
ndk-compile the help message was displayed.
Merge pull request #13 from datalogics-bhaugen/allow-specifying-ndk-at-command-line

Allow specifying android ndk to use at command line
Fix off by 1 error on CFI generation.  First element is 2 not zero.
Merge pull request #14 from bibliolabs/develop

Fix off by 1 error on CFI generation.  First element is 2 not zero.
Added jni::Pointer and jni::PointerPool classes to allow storing smart pointers on C++ side that have been passed to Java side, preventing early deletion. Storage is tested and working, now release needs testing with some closeBook() function on Java side.
Finished the Pointer and PointerPool and tested the lifecycle of containers and packages.
Merge branch 'feature/txtr-s1-sharedptrs' into develop
New template classed to ease JNI handling of Java classes, fields, arrays and many others.
Implemented a Java version of the Library class. This was implemented as pure Java class, since the C++ class didn't implement anything interesting to the Java side. Also started an IRI class, but didn't have time to finish. As it is now is building so I push this version to finish sprint 0.8. Work on IRI will continue next sprint.
- Fixed off by 1 bug.  CFIs are even and start at 2, while the list holding the spine items is zero based.
Merge pull request #15 from bibliolabs/develop

- Fixed off by 1 bug.
Some improvements to JNI helper classes, including Method and String access and better Exception handling and throwing.
Finished IRI java class and it's JNI layer.
Merge branch 'feature/txtr-s2-library-iri' into develop