Fixed multiline nodes (see #65)

[lyokha]

Note that the upper node gets matched against values from config.patterns.default using get_type_pattern() which returns a regexp (i.e. the original value, say function gets returned as %f[%w]function%f[^%w] having been wrapped with word_pattern()): this means that key ['function'] in last_types must be wrapped this same way (as [word_pattern('function')]) because its finally gets retrieved with last_types[type].

Note also that function_declaration may be deeply nested inside function_definition (at least, in C), and therefore a correct implementation requires a recursive traversal of nodes which is implemented with function find_node() introduced in this commit.

Closes #65

[romgrk]

Cool, thanks :)