Add Neuropixels 1.0e Headstage

[bparks13]

This PR adds the Neuropixels 1.0e headstage as an available option to be selected in the drop-down menu for headstages.

Fixes #55
Fixes #65 (add labels to differentiate 1.0f and 1.0e headstages)

[aacuevas]

Please review the units.
In different places they might appear as
µV, uV or �V (the latter being a non-ascii code)

Also, since this PR is changing to std::string objects, which are encoding-agnostic, it would be interesting to know what the GUI drawing methods use, because the "micro" sign is not standard ASCII, and thus it has a different encoding in UTF-8 or ASCII, so using a different encoding from what the GUI uses to print might result on display issues.

Juce::String hides this, since it uses utf-8 internally by default and has methods to convert between encodings, so this might be a little tricky as care needs to be taken manually. This is probably one of the reasons Juce::String is still part of the library, as it does offer extended functionality not present on std::string (unlike ScopedPointer, which became obsolete with C++11's std::unique_ptr and other smart pointers)

[aacuevas]

Seems good