Implement error checking in new GUI

[BrianLandry]

I think the way to do this is simply have the text of each tooltip be {{tText[ng-model]}} where ng-model is the model of the associated input box. This will create a relationship between the ng-model object and the text that is displayed in association with it. So when you go through and validate the model, when parameters are found to be invalid, you can just set their associated text via tText[ng-model]="tooltip error text".

[SynbioLucas]

All Level 1 validation (i.e. checking input fields, but not comparing them to any other fields) is now complete except for Arb Waveforms. That will be handled in #181. (As of 5fd3ab73a672b410e3b9a2f5a30b8ebd86d8c70c.)

[SynbioLucas]

Level 2 error checking complete, but not fully functional (as of 288ed8ea39598743823c8dea627c2e3ca487b3c6):

• Checking that a channel is only selected once per experiment
  • Tooltip for this doesn't seem to appear, though all the validation runs correctly (see #200)
• Checking that Experiment timepoints are entered correctly

Next is Level 3 error checking: comparing values across experiments to make sure that a valid number of wells is being used in each.