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-ca2.key

@@ -0,0 +1,6 @@
+-----BEGIN EC PRIVATE KEY-----
+MIGkAgEBBDCD2RUOoHHwVxAzozi4hsGmEV1ttAPhKXZF14dvI6tEIOpke4WxdueF
+lap01tGkXuqgBwYFK4EEACKhZANiAATD2is0QTdYL4dW/vyJuilDS07gbsMOV1Mz
+OVjUUrSRlTkLI99fFyRiSPwalSnOLC2HwohSgK/Waqsh3bjTHG5YuMrosmmO80Gt
+KcO0X3WnR2/VGSlVaZpTOyC0ZhZgMx4=
+-----END EC PRIVATE KEY-----