Add support for other languages (e.g i18n)

[luandro]

There's not much to translate so far, and would be the app much more accessible.

[dullage]

This is a great idea. My only concern is that the search index is currently optimised for the English language. I can imagine it would work fine with many other languages but there are certainly some optimisation steps that non-English languages wouldn't benefit from. Take a look on my comment on #38.

Are you currently using flatnotes with non-English text?

[kangfenmao]

I use Flatnotes for Chinese note searches. In fact, English indexing works fine, but when I search for Chinese, I always get no results. @dullage

[6drf21e]

I use Flatnotes for Chinese note searches. In fact, English indexing works fine, but when I search for Chinese, I always get no results.

Chinese characters can not be matched to the index, I am using # tags to retrieve the way, in addition to find [space] Chinese [space] in the content can also be retrieved.

中文字符不能被匹配索引，我是用 #标签 的方式来检索，另外发现 [空格]中文[空格] 中的内容也可以被检索到。