Change help buttons colour and add them relief

[Ana06]

Change help buttons colour and add them relief to make them more recognizable

[apoorv9990]

Created PR 22: #22.

Also I was thinking that instead of showing a new Activity on help click maybe we can show the help text in a dialog.

[Ana06]

But a Dialog is normally used for telling the user to make a decision into diferent options. It is true that they can also be used to render extra information, but the Dialogs don't fill the screen and some of our helps messages are really long, so probably it is not a good option.

Why do you want to use Dialogs?