Switch to cmake (#49)

Switch to cmake (#49)

* cmake: set default Release build type

* cmake: optionally enable cxx

* cmake: enable bindings with static library

* cmake: build testopt

* cmake: enable cxx for python bindings

* cmake: install nlopt.pc

* cmake: added missing compiler checks

* cmake: add octave support

* cmake: add guile bindings

* cmake: provide package_source target

* cmake: generate api headers

* Add Appveyor config file

* Test MinGW build

* Removed autotools

* cmake: install man

* re-implement getopt for test

* travis: +osx

* cmake: man/pkgconfig unix only

* add only Python test if built

* cmake: pkgconfig on mingw

* Fix octave include

* Find numpy includes

* Detect SWIG at top-level

* cmake: RPATH policy

* appveyor: shared build

* Add cmake config files

* travis: shared builds

* appveyor: no shared builds

* BUILD-MINGWXX.sh are superseeded by toolchain files