Refactor exp package
linting exp/prepare.py for #9
Rename PdfSlider to Slider in exp.matching
Rename PdfSlider to Slider in exp.exp_common
Rename PdfSlider to PdfReader, and simplify funtions, seperate to summary.Slider
import summary would cause looping dependency, so remove it.

This should be check and test as metioned in #29
Add slide path, pages information. Moved from exp_common
lint exp.feats for #9