FUTURE
* allows pipes (|) for commands

0.8.0
* add ; at end of line to suppress return value output
* Remove message spam (before/after hooks)
* stop commands returning a value and allow all statements to suppress
   values being returned by ending line in ';'
* use `redo` in the r() method when encounter a command
* shell functionality should just use system(), but redirect in and
   out to Pry.input and Pry.output by reassining $stdin and $stdout
   for duration of block.
* basicobject and no to_s/inspect support
* fix documentation, support rdoc and yard properly
* only load Ripper if 1.9 AND MRI (support jruby 1.9, using
   RubyParser)
* secret :cd and :pwd and :ls commands
* supercharge cat-file so it can syntax highlight sourcecode files


0.7.0
* add pry-doc support with syntax highlighting for docs
* add 'mj' option to ls (restrict to singleton methods)
* add _ex_ local to hold last exception raised in an exception

0.6.8
* add whereami command, a la the `ir_b` gem
* make .pryrc be loaded by run-time pry sessions

0.6.7
* color support
* --simple-prompt for pry commandline
* -I mode for pry commandline
* --color mode for pry commandline
* clean up requires (put them all in one place)
* simple-prompt command and toggle-color commandd.

0.6.1
* !@ command alias for exit_all
* `cd /` for breaking out to pry top level (jump-to 0)
* made `-e` option work in a more effective way for `pry` command line invocation
* exit and exit-all commands now accept a parameter, this parameter becomes the return value of repl()
* `command` method from CommandBase now accepts a :keep_retval arg that determines if command value is returned to pry session or just `nil` (`nil` was old behaviour)
* tests for new :keep_retval and exit-all/exit behaviour; :keep_retval will remain undocumented.

0.5.0 release:
* !!!! UPDATE DOCUMENTATION !!!!
* Use clipped version of Pry.view() for large objects
* Exit Pry session on ^d
* Use Shellwords for breaking up parameters to pry commands
* Use OptionParser to parse options for default pry commands
* Add version command
* Refactor 'status' command: add current method info
* Add meth_name_from_binding utility lambda to commands.rb
* Add -M, -m, -v(erbose), -a(ll), -s(uper), -l(ocals), -i(ivars), -k(klass vars) options to ls
* add -i(nstance) option to show-method
* add --help option to most commands
* Get rid of ls_method and ls_imethods (subsumed by more powerful ls)
* Get rid of show_idoc and show_imethod
* Add special eval-file command that evals target file in current context