Added translation for `nr_low`.
file limits: 3MB->5MB image limits: 2560x2560->3000x3000, 1280x1280->1500x1500
- Updated `description`, `show_demonstration`, `go_to_github`, `upscaling`, `file_limits`. - *Agrandissement* (enlargement) -> *Mise à l'échelle* (upscaling). - Added translation for TTA-related strings.
- Added translation for 'nr_highest'. "Maximale" sounds like a better fit than "Très haute" (Very High) or "La plus haute" (translated literally). - Updated description. - [URL is feminine in French.](https://fr.wikipedia.org/wiki/Uniform_Resource_Locator) - [artefacts -> artéfacts.](https://en.wiktionary.org/wiki/Appendix:French_spelling_reforms_of_1990) - [MB -> Mo.](fr.wikipedia.org/wiki/Octet) - [Unlike English, French has a space before colons.](http://www.oxforddictionaries.com/words/french-usage-notes-for-english-speakers-translating-into-french-33-spelling-and-punctuation) - Various improvements.