geohex 3.2.0+5

Dart implementation of Hexagonal geo-coding system (GeoHex.org) encoding.

3.2.0+1

• Initial version.
• Precision clamping

3.2.0+2

• Added some tests

3.2.0+3

• Added missing export of zone.dart, thanx synw

3.2.0+4

• Renamed clamp to clampPrecision
• Internal code minificatication
• Improved test coverage
• Separated unit test and geohex.net testcases
• Fixed potential crash in adjustXY method

3.2.0+5

• merged back geohex_net test file into geohex_test
• added more tests