Changes in Version 0.1.5

  * add function has been renamed to add.bizdays

  * Calendar's argument weekdays default value is NULL

  * Calendar has new arguments: dib, adjust.from, adjust.to

  * travis-ci integration

  * New functions: bizyears, bizyearse, bizdayse
  
  * bizdays accepts NA values in both arguments, from and to

Changes in Version 0.1.4

  * bizdays, adjust.previous, adjust.next and is.bizday accept POSIXct
  and POSIXlt objects.
  
  * bizdays, adjust.previous, adjust.next and is.bizday handle NA values
  without break

  * bizdays, adjust.next and adjust.previous are fast
