🆒 Add extended syntax

[belozer]

Add new syntax for write short css.

:block(block):mod(mod1):mod(mod2) :elem(elem):mod(mod)
.block_mod1.block_mod2 .block__elem_mod

or

```less
:block(block) {
    &:mod(mod) {
        :elem(elem) {
           // -> .block_mod .block__elem
        }
    }
}

[codecov-io]

Current coverage is 100%

Merging #4 into master will not change coverage

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[belozer]

THIS IS PROBLEM PR! Bad works with pseudo elements! 💣

[mistadikay]

Hi @belozyorcev. Thank you for your PR, we really appreciate it and it will be reviewed in a day or two. Unfortunately I don't have time at the moment (not sure about @deepsweet)

[deepsweet]

imo splitting this into 2 logical parts is a good idea:

1. multiple :mod()
2. :elem() with block context

but generally it looks almost good to me :)

[belozer]

I fix problems with pseudo.
And added optional syntax.

• , delimeter (for mod val)
• -> delimiter (for mod val)
• ' single qoutes :block('b'):mod('m', 'v')
• " double qutes :block("b"):mod("m", "v")

Next I'll work on pobems v1.0.0 with the new syntax.