Blimp: add support for SSL connections.

blimp/docs/running.md

 # Running Blimp
 
 See [build](build.md) for instructions on how to build Blimp.
 
 ## Running the client
 
 There are both Android and Linux clients.  The Android client is the shipping
 client while the Linux client is used for development purposes.
 
 ### Android Client
 
 Install the Blimp APK with the following:
 
 ```bash
 ./build/android/adb_install_apk.py $(PRODUCT_DIR)/apks/Blimp.apk
 ```
 
 Set up any command line flags with:
 
 ```bash
 ./build/android/adb_blimp_command_line --your-flag-here
 ```
 
-To have the client connect to a custom engine use the `--blimplet-endpoint`
-flag.  This takes values in the form of scheme:ip:port.  The possible valid
-schemes are 'tcp', 'quic', and 'ssl'.  An example valid endpoint would be
-`--blimplet-endpoint=tcp:127.0.0.1:25467`.
+To have the client connect to a custom engine use the `--engine-ip`,
+`--engine-port`, and `--engine-transport` flags. The possible valid
+values for `--engine-transport` are 'tcp' and 'ssl'.
+An example valid endpoint would be
+`--engine-ip=127.0.0.1 --engine-port=1234 --engine-transport=tcp`.
+
+SSL-encrypted connections take an additional flag
+`--engine-cert-path` which specifies a path to a PEM-encoded certificate
+file (e.g. `--engine-cert-path=/path/to/file.pem`.)
 
 To see your current command line, run `adb_blimp_command_line` without any
 arguments.
 
 Run the Blimp APK with:
 
 ```bash
 ./build/android/adb_run_blimp_client
 ```
 
@@ skipping 75 matching lines @@
 
 ```bash
 out-linux/Debug/blimp_engine_app \
   --use-remote-compositing \
   --disable-cached-picture-raster \
   --blimp-client-token-path=/tmp/blimpengine-token \
   --user-data-dir=/tmp/blimpengine \
   --enable-logging=stderr \
   --vmodule="blimp*=1"
 ```