[lib] Creation of I/O decorated functions.
[pep8] Fix some trailing spaces, >80chars lines, etc.
[core] Check if tmp logfile exists before reading from it.
[owtf] Revert previous permissions checking function.

Reverted commits:

+ 5c410e9def6985daa3928037d510104bae373836
+ 7aef0248d7b9f8c157279faad360482a6ff8c572
+ 3157669da1b4dfe331f2b146f4879244912a7dec
+ 71df07b018a218b2fbde441f7b10d9ab1fd0a601
(Fix #242) Force OWTF to use i/o decorators.

The decorated i/o functions will properly exit OWTF if a perm error is raised
when opening/reading/creating files/directories.

**Discussion**

Maybe the `open()` function should be decorated. What do OWTF contrib think?
[Plug-n-Hack] Changed URL for PAC file in ui_handlers, now browser configures to OWTF proxy not UI server, added comments to ease understanding later
[core] Move I/O decorators to Core.

Plus, catch all OSError/IOError instead of only perm ones.
(Fix) Allow decorated I/O functions to not force owtf to quit.

*Bug*

For instance, with the following snippet:

    :::python
    try:
        a = core.open('asdasd', 'r')
    except IOError:  # Never catched because OWTF exited before.
        pass

This would force OWTF to clean.

*Fix*

Now, the user can specify `owtf_clean=False` that will skip the exit and solely
raise the error.

    :::python
    try:
        a = core.open('non_existing_file', 'r', owtf_clean=False)
    except IOError:  # IOError will be catched now.
        pass
Use decorated `open()` function when opening a file.
[core] Update doc on i/o decorator.
[core] Fix typo.
[Remove files] Clean repository of not needed files in /framework/http/proxy/templates/, before this template files were used for Plug-n-Hack configuration by OWTF proxy, now Plug-n-Hack is configured using UI and template files are in /framework/interface/templates/pnh/
[core] Remove import *
[lib] More pythonesc RemoveListBlanks.

Is this function even useful? I don't clearly see why this has been exported to
a specific function since it takes one line to achieve the same thing.
(Fix #252) Force the string to be unicode.
[Proxification] Temporarily removed proxychains commands from Skipfish tool, for more details: https://github.com/owtf/owtf/issues/253
[error_handler] Small PEP8 fixes.

+ 80 chars on the license.
+ Remove import *
[lib] Remove unused `GetDictValueOrBlank` function.

This functions only does a dict.get(key, '').
So better use `.get()` than `GetDictValueOrBlank`.
[lib] Use `set` instead of `GetUnique`.

+ Remove `GetUnique`
+ Replace old references to `GetUnique` by `set`
[lib] Move exceptions to another module.