Support for PC platform (#12)

* improvements for cross-platform compiling

* moved tactility-core to libs/

* splitup improvements

* remove git/gitmodules from freertos

* better platformbetter platform checks

* added build scripts

* delete mbedtls

* re-add mbedtls

* fixes and improvements

* added pc build

* simplify build scripts

* revert build scrpit

* updated builds

* fix for pc

* fix for pc

* fix for build

libs/mbedtls/tests/data_files/ec_521_prv.comp.pem

@@ -0,0 +1,6 @@
+-----BEGIN EC PRIVATE KEY-----
+MIGYAgEBBEIBsbatB7t55zINpZhg6ijgVShPYFjyed5mbgbUNdKve9oo2Z+ke33Q
+lj4WsAcweO6LijjZZqWC9G0Z/5XfOtloWq6gBwYFK4EEACOhRgNEAAMAHeFC1U9p
+6wOO5LevnTygdzb9nPcZ6zVNaYee5/PBNvsPv58I+Gvl+hKOwaBR0+bGQ+ha2o/6
+zzZjwmC9LIRLb1Y=
+-----END EC PRIVATE KEY-----