version 0.15 - release 1

Main features of this release are:

• data cache compilation option ENABLE_CACHE enabled by default
  • data trees require ~20% more memory
  • operations on these trees are much faster (depends on their size, on 20k nodes around 100-times faster)
• internal ietf-yang-library model updated
• new schema printer format tree-rfc
• extension validation callback
• error handling overhaul (more in DOCs)
• yang-data extension support
• support for user type plugins
  • that can perform additional validation or custom value storing
• json data printer fixes so that it should be equal to xml
• static build support
• loads of minor or major bugfixes and enhancements