add a flare finder to varbase (or a new module that does this)

[waqasbhatti]

for methods, see:

• https://arxiv.org/abs/1607.03494
• http://adsabs.harvard.edu/abs/2015ApJ...814...35C
• http://adsabs.harvard.edu/abs/2011AJ....141...50W
• http://adsabs.harvard.edu/abs/2014ApJ...797..122D

this is basically a matched-filter convolution with a trend-filtered light curve. the flare finder should keep a list of all flares it finds, along with their start and end times, integrated flux between flare and continuum, and perhaps a measure of the energy based on rough stellar luminosity based on its color (assuming it's a dwarf)

[lgbouma]

Relevant implementations from the last reference (perhaps these were already the plan?): https://github.com/jradavenport/flare-decomp/blob/master/aflare.py