#24: support string pattern matching

[cedricduriau]

Fixes #24 Based on #62

Description

Add support for string pattern matching as selection mode.

Currently using string.gmatch as core logic simply because:

• ships with standard lua string library
• leverages the entire lua pattern matching syntax

Ideally I'd prefer using the POSIX fnmatch logic, but due to the sheer size of code to support this in lua it does not ship with the standard library. An external library does exist. Links below.

Changes

• add selection mode "Pattern"
• support string.gmatch lua pattern matching

Links

• Lua pattern syntax: https://www.lua.org/pil/20.2.html
• Lua pattern tutorial: http://lua-users.org/wiki/StringLibraryTutorial
• Lua POSIX library: https://github.com/luaposix/luaposix/

Screenshots