Import sipcalc v1.1.6

Import of http://www.routemeister.net/projects/sipcalc/ v1.1.6 by
Simon Ekstrand:

  * Fix multiple buffer overflows. Patch from Jaromir Capik.
  * Fix multiple spelling errors. Suggestions from Ross Richardson.
  * Version 1.1.6

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>