support Raspberry Pi Raspbian configure.sh
Add contributing guidelines
Install pylint on the build.

* Add pylint to test requirements.
* Do not clutter output with files that are OK.
* Activate pylint if flake8 finds no errors.
* Ignore selected errors for now.
* Ignore selected warnings for now.
* Ignore selected conventions for now.
* Ignore selected refactors for now.
* Ignore selected fatals for now.
Drop flake8 for now.
Fix some pylint errors.

* E0602: Fix undefined variables. Refactor some `from X import * `
  cases, while we are at it.
* E1205: Fix arguments for logging format strings.
* E1305: Fix arguments for format strings.
Fix some pylint warnings:

* W0102: Disallow mutable values as default arguments.
  Check http://bit.ly/1sJ78fm for why mutable default
  arguments might not behave as expected.
* W0104: Explicitly denote seemingly pointless statement.
* W0105: Fix string positioned as statement.
* W0107: Drop unnecessary pass statements.
* W0231: Call __init__ of parent class.
* W0403: Honour relative imports.
  * Make the code more self-documented.
  * Ease the transistion to Python 3.
* W0611: Drop unsed imports.
* W0612: Fix unused variables and functions.
  * Comment and label unused functions.
  * Use _ for unused variables in unpacking statements.
* W0622: Avoid variable names that shadow builtins.
Fix some pylint conventions.

* C1001: All classes should be new-style classes.
* C0325: Drop unnecessary parens.
Fix some pylint refactors.

* R0201: Declare static methods as such.
Fix docstrings.
Merge pull request #621 from Renelvon/pylint_checks

Accept the pylint challenge.
Various typo fixes suggested by @renelvon
checkstyle.sh: fix for environments where pylint != pylint2

Signed-off-by: Thomas Stilwell <stilwellt@openlabs.co>
configure.sh: osx: prefer local pysqlcipher over fetching remotely

the remote version seems not to work consistently; local install seems ok

an explanation is not forthcoming, but this fix apparently works

Signed-off-by: Thomas Stilwell <stilwellt@openlabs.co>
Merge pull request #632 from benemorius/pylintfix

checkstyle.sh: fix for environments where pylint != pylint2
Revert PR #621
Merge pull request #633 from dionyziz/revert_621

Revert PR #621
remove -j option
Merge pull request #613 from y12studio/pi-raspbian-conf

support Raspberry Pi Raspbian configure.sh
Improve CONTRIBUTING.md

* Add sections about code and PR documentation.
* Restructure finding-an-issue section.
* All kind of style fixing
Merge pull request #1 from Renelvon/contributing

Restructure and expand CONTRIBUTING