Update README

Adds teamcity build status icon
Moves README to README.md; minor formatting improvements
Merges README
Merge branch 'master' of git://github.com/maesenka/geolatte-geom into maesenka-master-mortoncodes
Adds minor documentation and test improvements.
Reduces number of JTSGeometryOperations objects
Merge pull request #23 from JeroenVu/master

Reduces number of JTSGeometryOperations objects
Reduces visibility of some MortonContext methods.

Corrects a naming mistake (numberOfLeaves did not return the number of
leaves, but the square root of number of leaves).
Fixes bug for MortonCode

MortonCodes were incorrectly calculated for contexts where extent height is
different from width.
Extends MortonCode interface with envelopeOf(mortoncode) method.
Merged with upstream.