Adding Macro functionality to remote

Macros can now be defined in config.json. See
example_configs/config.json for an example.

Macros allow you to define N commands to be run from one HTTP endpoint.
Macros currently appear as yellow buttons beneath the remote buttons.

In my testing I found 100msec between commands to be sufficient.
Merge pull request #6 from alexbain/macros

Adding Macro functionality to lirc_web