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/cli2.key

@@ -0,0 +1,5 @@
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIPb3hmTxZ3/mZI3vyk7p3U3wBf+WIop6hDhkFzJhmLcqoAoGCCqGSM49
+AwEHoUQDQgAEV+WusXPf06y7k7iB/xKu7uZTrM5VU/Y0Dswu42MlC9+Y4vNcYDaW
+wNUYFHDlf5/VS0UY5bBs1Vz4lo+HcKPkxw==
+-----END EC PRIVATE KEY-----