Update sbt version

• Update SBT Version
• Fix minor bugs

Add scala 2.12 support

• Scala 2.10 support is deprecated now.

Fix problem with library usage in multiple threads

Due to ronmamo/reflections#81 we were not able to use library in multiple concurrent threads. This release fixes this problem and adds couple minor bug fixes

v2.1

• Added NL Locale
• Added bsn number generation method
• Added username generation method

Big refactoring

• Extended Calendar generator
• Introduced URL Builder
• Introduced User Agent builder
• Relative Date objects generation
• Refactoring that improves memory consumption
• Introduced SSN generator
• Improved csv file generation
• Extended File Generator