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/rsa522.key

@@ -0,0 +1,9 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIBPgIBAAJCAtMCdT492ij0L02fkshkdCDqb7yXwQ+EmLlmqVPzV2mNZYEGDf4y
+yKuY20vFzirN8MHm5ASnWhMoJVDBqjfTzci/AgMBAAECQU05ffxf7uVg74yC9tKg
+qCa746NpMh3OM+HZrUxiOXv0sJMRXNEPD5HNLtgcNY6MI5NYbUvkOXktnFZpxWYP
+TH7BAiEeFJGs5Z6gRd2v/IbYLMFDHgjqho04INGTOvnyI7lGVKUCIRgJM7moFuoM
+UrKTmJK1uOzauWEykCKgc6BGH6TGZoEWkwIhBzQn2v82qO1ydOYGKRk2w2sa+Yd1
+pH5/kkHqf+m8QjKdAiEQ9eVW+4J30wxD0JyX4b1E/S5UpN5KYNhWX0US+6D3NBsC
+IRxePzdQlutZWg0Cnku3QE1tOLBCFlP7QVVl5FbKcY5H5w==
+-----END RSA PRIVATE KEY-----