migrate bui-manage to click

New bui-manage commands using click.

See merge request !42

refactoring to be able to use click instead of Flask-Script

Allow the use [click](http://click.pocoo.org/5/) instead of [Flask-Script](https://flask-script.readthedocs.io/en/latest/)

See merge request !41

switch to burp 2 by default

default to burp 2

See merge request !39

various fixes + docker files

fixes

See merge request !38

improve BASIC:ACL documentation

Closes #168

See merge request !37

starting with burp 2.0.48 it is possible to return the entire manifest for the tree view (see #23)

This feature was kind of requested for a long time in #23

Keep in mind this feature is CPU, MEMORY and BANDWIDTH consuming.

See merge request !36

python3 compatibility

Closes #174

See merge request !35

Resolve "can't add client via burp-ui"

Closes #172

See merge request !34

bui-agent was not starting without -v using python 3 (fix #169)

Closes #169

See merge request !33

fix: setup.py

fix

See merge request !32

some fix for the demo + cosmetic

improve demo

See merge request !31

add: demo mode

disable some features while running the demo

See merge request !30

improve ua detection

support iPhone + iPad

See merge request !29

fix build

fix

See merge request !28

fix packaging

packaging

See merge request !27

fix: packaging of js files

fix

See merge request !26