Bugfixes/string

[SGSSGene]

This pull request fixes several issues when viewing std::string

1. It is possible to call cppman string::string
2. The link to basic_string::npos works now
3. formatting of erase/erase_if inside of std::string is fixed
4. correcting formatting of stoi, stol, stoll inside of std::string
5. correct hightlighting of std::swap inside of std::string
6. updated data base for cppreference.com

Known issues - related to this PR:

• std::vector can't be viewed any more

probably unrelated issues:

• updating index database for cplusplus.com doesn't work (gets stuck on no_throw_t when crawling)

[SGSSGene]

I am still a little unhappy with this pull request.

1. As in the description, it doesn't allow to open std::vector<bool>
2. I can't open the page for std::fstream

I can live with std::vector<bool> not working, but std::fstream is really anoying, I will look into it the next few days.

[SGSSGene]

1. Now most lines in cppman/main.py should be fixed
2. cplusplus.com is fixed and can be crawled again
3. lookups for fstream work now

[aitjcize]

LGTM, sorry for the long delay, and thanks for fixing this :)

[aitjcize]

Can you also update the index database? We should release a new version soon.