Add morpheus integration test to Circle CI.

 * Tidy up the Circle CI script.

 * Add nightly build parameter to Circle CI.

 * Add comment in the Circle CI script explaining its purpose.

circle.yml

+# Purpose:
+# - To test and prove that a new commit in  the mbed TLS repository builds
+# and integrates with mbed-os properly.
+#           AND
+# - To test and prove that the current development head of mbed TLS builds
+# and integrates with the current mbed-os master branch.
+#
+# The script fetches all the prerequisites and builds the mbed TLS 'tls-client'
+# example. This script is triggered by every commit and once each night and the
+# exact behaviour depends on how it was triggered:
+# - If it is a nightly build then it builds the mbed TLS development head with
+#   mbed-os master.
+# - If it was triggered by the commit, then it builds the example with mbed TLS
+#   at that commit and mbed-os at the commit pointed by mbed-os.lib in the
+#   example repository.
+
+test:
+    override:
+        - cd ../mbed-os-example-tls/tls-client/ && mbed compile -m K64F -t GCC_ARM -c
+
+dependencies:
+    pre:
+        # Install gcc-arm
+        - cd .. && wget "https://launchpad.net/gcc-arm-embedded/4.9/4.9-2015-q3-update/+download/gcc-arm-none-eabi-4_9-2015q3-20150921-linux.tar.bz2"
+        - cd .. && tar -xvjf gcc-arm-none-eabi-4_9-2015q3-20150921-linux.tar.bz2
+        - ln -s ../gcc-arm-none-eabi-4_9-2015q3/bin/* ../bin/
+        # Install mbed-cli
+        - cd ../ && git clone https://github.com/ARMmbed/mbed-cli.git
+        - cd ../mbed-cli && sudo -H pip install -e .
+        # Get the sample application
+        - cd ../ && git clone git@github.com:ARMmbed/mbed-os-example-tls.git
+        # Get mbed-os
+        - cd ../mbed-os-example-tls/tls-client && mbed deploy
+        # Update mbed-os to master only if it is a nightly build
+        - >
+            if [ -n "${RUN_NIGHTLY_BUILD}" ]; then
+                cd ../mbed-os-example-tls/tls-client/mbed-os/ && mbed update master;
+            fi
+        # Import mbedtls current revision
+        - ln -s ../../../../../../../mbedtls/ ../mbed-os-example-tls/tls-client/mbed-os/features/mbedtls/importer/TARGET_IGNORE/mbedtls
+        - cd ../mbed-os-example-tls/tls-client/mbed-os/features/mbedtls/importer/ && make
+    override:
+        # Install the missing python packages
+        - cd ../mbed-os-example-tls/tls-client/mbed-os/ && sudo -H pip install -r requirements.txt