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/ChangeLog.d/fix-csr-parsing-with-critical-fields-fails.txt

@@ -0,0 +1,6 @@
+Features
+   * Add new mbedtls_x509_csr_parse_der_with_ext_cb() routine which allows
+     parsing unsupported certificate extensions via user provided callback.
+
+Bugfix
+   * Fix parsing of CSRs with critical extensions.