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/sha256-armce-arm.txt

@@ -0,0 +1,7 @@
+Features
+    * Support Armv8-A Crypto Extension acceleration for SHA-256
+      when compiling for Thumb (T32) or 32-bit Arm (A32).
+New deprecations
+    * Rename the MBEDTLS_SHA256_USE_A64_CRYPTO_xxx config options to
+      MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_xxx. The old names may still
+      be used, but are deprecated.