Add ability to pause spinner and get its status

[theckman]

This change adds three new methods to the Spinner type, and deprecates the Active method.

The first are the Pause() and Unpause() methods, which put the spinner in a paused state so that you can update multiple configuration options without users seeing a spinner rendered with partial changes applied. Such as changing the suffix, message, or colors.

The third method is the Status() method, which deprecates Active(). Because the internal state machine for the spinner has become more complex, it's no longer reasonable to consider it active or inactive. With this we include a new type, SpinnerStatus, and constants to represent each state of the internal state machine:

• SpinnerStopped
• SpinnerStarting
• SpinnerRunning
• SpinnerStoppping
• SpinnerPausing
• SpinnerPaused
• SpinnerUnpausing

[codecov[bot]]

Codecov Report

Merging #19 into master will increase coverage by 0.42%. The diff coverage is 89.09%.

@@            Coverage Diff             @@
##           master      #19      +/-   ##
==========================================
+ Coverage   92.05%   92.48%   +0.42%     
==========================================
  Files           2        2              
  Lines         340      386      +46     
==========================================
+ Hits          313      357      +44     
- Misses         14       15       +1     
- Partials       13       14       +1     

Impacted Files	Coverage Δ
spinner.go	92.24% <89.09%> (+0.47%)	:arrow_up:

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