shift level data w/ arr keys

meson: increment version number

feature: rectangle fill

add build manifest

meson: add explicit dependencies to -ldl and -lm

The link command might work without them when they're implicitly linked
from the glibc, but this it clearly not the case on all systems.

meson: add -D_GNU_SOURCE for MAP_ANONYMOUS

Required as per mmap(2).

fix: remove duplicate 'src/main.c' instance in meson.build

replace cmake with meson & use C99 instead of C89

This commit also takes care of all the warnings that didn't appear
with CMake. I decided to switch to C99 cause my code clearly wasn't
C89 compliant.

feature: window resizing (#1)

include/conf.h: use less specific values

Feature: middle click in editor to pick a tile

Updated the README in consequence.

fix: variable array length in C90, code wouldn't compile

Tile first config option (-tile-first)

Flags for background color configuration

config: background color options for editor and picker

fix: level rendering was broken with rectangle tilesets

Level creation flag & cleanup and improved README

editing_area/level.c: Specify char signes

Fix very bad casting mistake & dummy verbose mode

fix: level drawing was broken