Merge branch '1882_esc_seq_in_replace_field'
* 1882_esc_seq_in_replace_field:
Remove replace_prepare_t type and use defined constants for use just one type (int) in functions
Despite of the fact that algorithm now ignores the absence of closing curly brace '}' (which probably isn't 100% correct), this should be checked in tests for replace_handle_esc_seq function, not process_escape_sequence - it is the replace_handle_esq_seq who decides whether it is an escape sequence or not.
added tests for mc_search_regex__replace_handle_esc_seq() function
str_isutf8() function now returns gboolean value
Ticket #1882: PCRE search: escape sequence support in replacements, UTF8 support (just a flag for libPCRE)