small flake8 changes

[anarcat]

followup for #4: we configure flake8 to be a little more strict so that new contributions are cleaner. i also fix errors i introduced in recent pull requests, to try to play catchup at least with the new stuff i submitted.

finally, i added a blurb to the development docs about flake8, because i had forgotten about it...

before this PR:

1       E121 continuation line indentation is not a multiple of four
1       E125 continuation line does not distinguish itself from next logical line
25      E127 continuation line over-indented for visual indent
1       E128 continuation line under-indented for visual indent
1       E202 whitespace before ']'
1       E203 whitespace before ','
1       E221 multiple spaces before operator
1       E222 multiple spaces after operator
1       E225 missing whitespace around operator
1       E261 at least two spaces before inline comment
3       E271 multiple spaces after keyword
5       E301 expected 1 blank line, found 0
12      E302 expected 2 blank lines, found 1
1       E303 too many blank lines (2)
12      F401 '__version__' imported but unused
10      F811 redefinition of unused 'cmd' from line 13
4       F812 list comprehension redefines 'action' from line 1463
2       F821 undefined name 'sys'
2       F841 local variable 'e' is assigned to but never used
1       W291 trailing whitespace
3       W293 blank line contains whitespace
4       W391 blank line at end of file
93

(and in the above, i deliberately skipped recursing into .tox, which it does by default now, which triples everything. this PR also fixes that.)

after this PR:

2       E121 continuation line indentation is not a multiple of four
5       E122 continuation line missing indentation or outdented
2       E125 continuation line does not distinguish itself from next logical line
25      E127 continuation line over-indented for visual indent
1       E128 continuation line under-indented for visual indent
1       E202 whitespace before ']'
1       E203 whitespace before ','
1       E221 multiple spaces before operator
1       E222 multiple spaces after operator
1       E225 missing whitespace around operator
1       E261 at least two spaces before inline comment
3       E271 multiple spaces after keyword
5       E301 expected 1 blank line, found 0
10      E302 expected 2 blank lines, found 1
1       E303 too many blank lines (2)
1       E401 multiple imports on one line
62      E501 line too long (149 > 120 characters)
9       F401 'DistutilsOptionError' imported but unused
10      F811 redefinition of unused 'cmd' from line 13
4       F812 list comprehension redefines 'action' from line 1463
3       F821 undefined name 'sys'
2       F841 local variable 'e' is assigned to but never used
1       W291 trailing whitespace
3       W293 blank line contains whitespace
4       W391 blank line at end of file
159

about 30 of those are fixed in #316 as well.

[ThomasWaldmann]

the initial configuration might have been in a way so stuff that is not fixed yet (but present) does not fail all the time, so only new issues are discovered. one can then remove exlusions when fixing the corresponding issues without having it to do all at once (or having it fail all over the place all the time).

[ThomasWaldmann]

did you notice the travis failure?

[anarcat]

i did not notice the test failure, i'll take a look.

the initial configuration was indeed a way to get flake8 working without too many warnings, but it seems it was too enthusiastic at censoring errors, at least from my perspective... 120 errors is certainly managable, especially since half of those are line length...

[anarcat]

tests should pass now.

[codecov-io]

Current coverage is 82.84%

Merging #318 into master will decrease coverage by -0.01% as of 52fd8a9

@@            master    #318   diff @@
======================================
  Files           34      34       
  Stmts         7075    7072     -3
  Branches         0       0       
  Methods          0       0       
======================================
- Hit           5862    5859     -3
  Partial          0       0       
  Missed        1213    1213       

Review entire Coverage Diff as of 52fd8a9

---

Uncovered Suggestions

1. +0.60% via borg/fuse.py#126...167
2. +0.48% via borg/xattr.py#199...232
3. +0.41% via borg/xattr.py#166...194
4. See 7 more...

Powered by Codecov. Updated on successful CI builds.