Providing an api for disableTimeouts() in tests.

[jsdevel]

/cc @travisjeffery

This is in response to some feedback for #1262 after it was merged.

Please let me know what you think. Thanks.

[jsdevel]

@travisjeffery I'm not sure the specs would be able to modify disableTimeouts at that point in time as the timeout would have already been issued. Can you give me some guidance? I wasn't aware that this.timeout() had no cascade effect. All is well now.

[travisjeffery]

ok see my inline comments and use this api to do #1262

[jsdevel]

@travisjeffery do you mean that you'd like the tty flag removed?

[travisjeffery]

don't worry about it, i'll fix it.

[jsdevel]

@travisjeffery will mocha be able to signal _mocha that it's in debug mode? I was thinking the main use case for --disable-timeouts would be to handle this scenario.