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/test-int-ca2.key

@@ -0,0 +1,6 @@
+-----BEGIN EC PRIVATE KEY-----
+MIGkAgEBBDAtxOHUV4be1MdH1frBHzxITCyUSxrVjJN8QTvTVk558ka0a3zhd4Pb
+ekWt7wBPXQegBwYFK4EEACKhZANiAATw6KHd9flIt43V2YWdxCVYzD35jqxduWGW
+tcHGFfGPB3CkIcQ2f5+hRV2uphVhrtK6/dBV47qcnX0fdA2LFbyKTU/6HGxtqrxu
+1rvy8DIeYLgSZdAuDXDujFv1DzapfVg=
+-----END EC PRIVATE KEY-----