Spectro background color

[BryonLewis]

resolves #238

• Issue was caused by v-color-picker returning rgb( r g b / undefined) sometimes when returning strings. Updated the text strings to filter out this issue

Other things done while in the code:

• Update to a stable Vuetify version from a Beta Version
• Updated the background color so it could set the whole maps background. I.E it would change all colors instead of just the spectrogram.
• Removed 'blackBackground' references since 'backgroundColor' is now used.
• Created some functions for determining what text and grid/legend lines color should be. I.E if you make the background white the text should swap to black.
• Hide vertical markers for time endpoints for pulses/sequences when zoomed out.
• Added functionality to save a user's backgroundColor and color scheme to localStorage and use that instead of always relying on a default from the config of a user.

BATAI-SpectroBackgroundUpdate_small.mp4

[naglepuff]

LGTM!