Remove frog from the repository.

frog/README.txt

-Frog is a dart compiler implemented in dart.  It is currently focused on
-compiling dart code to efficient and readable javascript code.  However, it
-is ultimately intended to be the basis for future code analysis tools and
-development environments when these can be built in dart as well.  Two
-very early examples of this kind of use are in the samples directory:
-  * doc.dart - minimal documentation generator
-  * ifrog.dart - minimal command-line REPL for dart
-
-
-
-To use frog:
-
-1) Frog is now included in the checkout of the public repo of the bleeding_edge
-   branch. The code will be located under dart/frog.
-
-2) From the dart/frog directory, run the presubmit script to check your
-   installation is all working.
-     frog$ ./presubmit.py
-
-
-BEFORE YOU SUBMIT
-
-Before you submit, you should:
-
-1) Run the html tests:
-
-  $ ./frog.py --html -- tests/htmltest.dart
-  $ ./frog.py --html -- tests/canvastest.dart
-
-   These will open a browser -- verify in the console that no errors
-   happened.
-
-2) Run the presubmit script:
-
-  $ ./presubmit.py
-
-Note:
-
-If you make any changes to files under tests, you are expected to ensure that
-you don't break any of the other configurations.  If you only change the status of tests for frog, you should be okay.  However, if you
-modify any of the tests themselves, please run the tests with both vm and
-dartc configurations before checking in.
-
-
-Details:
-
-You can use build.py and test.py (that are run by the presubmit script):
-
-  $ ../tools/build.py --mode=release,debug
-  $ ../tools/test.py --report -t 5 -p color --mode=release --component=frog language corelib leg
-
-The 'frog' component is frog running on the VM.