Readme : Add info about Nix shell support & cleanup.

Readme.md

@@ -7,11 +7,13 @@
 [Русская версия](/voronind/resume/releases/download/latest/voronind_ru.pdf)
 
 ## How to build.
+
 ```bash
 $ make
 ```
 
 ### Available targets.
+
 Taget | Description
 --- | ---
 all | Clean, build and open all languages.
@@ -21,25 +23,19 @@ en | Build English resume.
 ru | Build Russian resume.
 open | Open built resumes in default PDF viewer.
 
+### Nix shell support.
+
+```bash
+nix develop
+```
+
 ## Requirements.
+
 * `GNU/Linux` (not tested on other platforms).
 * `LuaLaTeX` for the document itself.
 * `ImageMagick` (optional) for colored icons.
 
-### Texlive setup.
-```text
-$ wget https://mirror.ctan.org/systems/texlive/tlnet/install-tl-unx.tar.gz
-$ tar -xf install-tl-unx.tar.gz
-$ rm install-tl-unx.tar.gz
-$ cd ./install-tl-*
-$ ./install-tl
-```
-
 ### Installing missing dependencies.
+
 When trying to build the project, lualatex may throw missing dependency errors.
 To install them use `$ tlmgr install $dependency`.
-
-## TODO.
-- [x] Change icon color on build.
-- [x] Fallback for using black icons if ImageMagick is not available.
-- [ ] Show warning if ImageMagick is not available.