Issue #1234 - standardize some string conversions

Issue #1234 - standardize some string conversions

Conversions of the form std::wstring(CString) can leave stranded, extraneous
constructors when the CString is converted to std::wstring, and the compiler
won't catch them. Changing these conversions to to_wstring(CString) ensures that
they'll be removed.

Removed a few completely extraneous explicit string constructors. Changed a few
idiomatic string constructions into calls to to_CString.

[Oleksandr, 2014-08-21 14:01:22]

This LGTM, though this codereview without implementation of to_wstring and
to_CString is kind of hobbled. I didn't see them in any other review yet.

[Eric, 2014-09-29 19:25:10]

On 2014/08/21 14:01:22, Oleksandr wrote:
> This LGTM, though this codereview without implementation of to_wstring and
> to_CString is kind of hobbled. I didn't see them in any other review yet.

Reviewed in http://codereview.adblockplus.org/6224768520945664/ and already
committed.

[Felix Dahlke, 2014-09-30 13:21:41]

This change looks fine, but please address my comment in
http://codereview.adblockplus.org/6224768520945664/.

[Felix Dahlke, 2014-10-07 14:39:59]

LGTM