Error when using `new_task()` method

[sdelquin]

Using new_task() with tool names as described in https://github.com/AndyCyberSec/pylovepdf#tools gives me some errors. Check this gist out. My output is the following:

TOOL: imagepdf
No module named 'pylovepdf.tools.imagepdf'
TOOL: officepdf
module 'pylovepdf.tools.officepdf' has no attribute 'Officepdf'
TOOL: pdfa
module 'pylovepdf.tools.pdfa' has no attribute 'Pdfa'
TOOL: pdfjpg
No module named 'pylovepdf.tools.pdfjpg'
TOOL: validatepdfa
module 'pylovepdf.tools.validatepdfa' has no attribute 'Validatepdfa'

This is a generalization of #15 and #16

⭐   BTW, thanks for your pretty work!