Cosmetic fix to error and warning reporting. Also don't report user abort (Ctrl+C) as error

Author: screamerbg

README.md

@@ -713,7 +713,7 @@ Here is a list of currently implemented configuration settings:
  * `target` - Define default target for `compile`, `test` and `export`, and is an alias to `mbed target`. Default: none.
  * `toolchain` - Defines default toolchain for `compile` and `test` can be set through `mbed toolchain`. Default: none.
  * `ARM_PATH`, `GCC_ARM_PATH`, `IAR_PATH` - defines default path to ARM Compiler, GCC ARM and IAR Workbench toolchains. Default: none.
- * `protocol` - Defines the default protocol used for importing/cloning of programs and libraries. Possible values are `https`, `http` and `ssh`. Default: `https`.
+ * `protocol` - Defines the default protocol used for importing/cloning of programs and libraries. Possible values are `https`, `http` and `ssh`. Use `ssh` if you have generated and registered SSH keys (Public Key Authentication) with a service like GitHub, GitLab, Bitbucket, etc. Read more about SSH keys [here](https://help.github.com/articles/generating-an-ssh-key/) Default: `https`.
  * `depth` - Defines *clone* depth for importing/cloning and applies only to *Git* repositories. Note that while this option may improve cloning speed, it may also prevent you from correctly checking out a dependency tree when the reference revision hash older than the clone depth. Google `shallow clone` if you'd like to know more about using shallow clones. Default: none.
  * `cache` (EXPERIMENTAL) - Defines local path that will be used to store minimalistic copies of the imported/cloned repositories and attempt to use them to minimize traffic and speed up future importing. Note that this is an experimental feature and should be used for stable and production-ready repositories only. Default: none (disabled).
 

mbed/mbed.py

@@ -132,12 +132,12 @@ def action(msg):
 
 def warning(msg):
     for line in msg.splitlines():
-        sys.stderr.write("[mbed WARNING] %s\n" % line)
+        sys.stderr.write("[mbed] WARNING: %s\n" % line)
     sys.stderr.write("---\n")
 
 def error(msg, code=-1):
     for line in msg.splitlines():
-        sys.stderr.write("[mbed ERROR] %s\n" % line)
+        sys.stderr.write("[mbed] ERROR: %s\n" % line)
     sys.stderr.write("---\n")
     sys.exit(code)
 
@@ -2225,7 +2225,8 @@ def help_():
     else:
         error('OS Error: %s' % e[1], e[0])
 except KeyboardInterrupt as e:
-    error('User aborted!', 255)
+    log('User aborted!', -1)
+    sys.exit(255)
 except Exception as e:
     if very_verbose:
         traceback.print_exc(file=sys.stdout)