ARM Toolchain: search compiler in PATH

Add CMake target for strip since these changes break adb_upload_to_bebop.

GCC users should add the cross compiler bin path to PATH (location of arm-linux-gnueabihf-g++).
Clang user should do the following:
* set CMAKE_CXX_COMPILER to clang++ by providing -DCMAKE_CXX_COMPILER=clang++ to cmake
* get GCC cross compiler - needed because Clang does not ship a CRT
* create a symlink for clang and clang++ in GCC cross compiler bin dir.
* add GCC bin dir to PATH

Signed-off-by: Nicolae Rosia <nicolae.rosia@gmail.com>

Tools/adb_upload_to_bebop.sh

@@ -42,10 +42,6 @@ if [[ $adb_return == "" ]]; then
     restart_px4=true
 fi
 
-${PX4_TOOLCHAIN_DIR}/gcc-linaro-arm-linux-gnueabihf/bin/arm-linux-gnueabihf-strip \
-  -R .comment -R .gnu.version \
-  ../build_posix_bebop_default/src/firmware/posix/px4
-
 ../Tools/adb_upload.sh $@
 
 # restart the process after uploading