core: overlong UTF-8 encoding and surrogates (U+D800-DFFF) are invalid.
core: check that string is not NULL in function string_strndup
core: add comment with return value of function string_strcasestr
core: check that string is not NULL in function string_convert_escaped_chars
core: check that "chars" argument is not NULL in function string_strip
core: add note about result that must be freed in function string_mask_to_regex
core: check that regex is not NULL in function string_regex_flags
core: check that regex is not NULL in function string_regcomp
core: check that timeval arguments are not NULL in timeval functions
core: return only -1, 0 or 1 in string comparison functions
doc: fix example for function strcasecmp_range in Italian plugin API reference
doc: fix style of C/Python examples in docs
core: display curl error after a failed download
core: fix socks5 proxy for curl downloads (closes #119)
core: update Japanese translations
Merge pull request #120 from l/translation_ja

core: update Japanese translations
doc: update Japanese auto-generated files
core: add option weechat.color.status_nicklist_count (closes #109, closes #110)
core: add option "-mask" in command /unset (closes #112)
core: fix evaluation of expressions with regex condition (closes #63)

The regex itself is not evaluated any more (so parentheses are kept).

Before the fix:
>> abcd =~ (?-i)^abc
== [0]
>> (abcd) =~ \(abcd\)
== [0]

After the fix:
>> abcd =~ (?-i)^abc
== [1]
>> (abcd) =~ \(abcd\)
== [1]