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_pub.pem

@@ -0,0 +1,6 @@
+-----BEGIN PUBLIC KEY-----
+MIGbMBAGByqGSM49AgEGBSuBBAAjA4GGAAQAHeFC1U9p6wOO5LevnTygdzb9nPcZ
+6zVNaYee5/PBNvsPv58I+Gvl+hKOwaBR0+bGQ+ha2o/6zzZjwmC9LIRLb1YAzujk
+ip5l0Jyt2J8jXe4F87imRr5xXx9n1bQ04P8jofwH73dAGT5A7v9vO839dlqpFVAz
+Uk/k8gX1RE4pLEwvasE=
+-----END PUBLIC KEY-----