feat(css): setting prettier parser option for CSS files (prettier#91)

Prettier supports the `parser` option to indicate the parser to be used when parsing text rather than a file.
This is necessary because it's difficult to detect the source file type without a file extension.
This fix uses the same logic Prettier does to determine if the parser should be `postcss`.
It also avoids running ESLint on .css, .less, and .scss files.

fix: pass filePath to eslint.executeOnText (prettier#87)

Some rules need to know the path of the file being linted to properly apply a fix.
Also makes eslint ignore the path if it's configured to be.

Closes prettier#86

fix: don't remove no-var and prefer-const from eslint config relevant…

… rules (prettier#83)

* docs(contributors): Add lukaszmoroz to the contributors table

* fix: Don't remove no-var and prefer-const from eslint config relevant rules

These rules are fixable thus should not be ignored by prettier-eslint when loading the config through getRelevantESLintConfig.

Closes prettier#82

fix: change the default values to match Prettier's defaults (prettier#80

)

* fix: Changed the default values to match Prettier's defaults

Trailing commas, single quotes, and bracket spacing default values were incorrect and not matching
Prettier's default values

* test: Updated tests to correctly handle new default values

feat: upgrade prettier to 1.3.0 (prettier#78)

fix(singleQuote): interpret eslint quote backtick as singleQuote false (

prettier#76)

fix(scripts): Set defaults for getValFromTrailingCommaConfig missings…

… keys in objectConfig (prettier#74)

Closes prettier#48

feat(fallback-options): allow passing custom fallbacks if no eslint r…

…ule (prettier#73)

* docs(contributing): use yarn instead of npm and fix typo

* feat(fallback-options): allow passing custom fallbacks if no eslint rule

Some users may want to be able to fallback to specific prettier options only in the case that the
rule cannot be inferred from the corresponding ESlint rule. We add a `fallbackPrettierOptions` to
the API to allow this. This is different than `prettierOptions` because those always override the
eslint rule, whereas fallback options are only used if the eslint rule is not found. If a fallback
option is not provided and an eslint rule is not found, the default prettier option is used as was
always the case.

Closes prettier#72

fix: trailingComma all only if functions enabled (prettier#71)

This is in line with eslint's defaults: http://eslint.org/docs/rules/comma-dangle

BREAKING CHANGE: trailingComma now defaults to prettier's `es5` option if it's not configured.

feat: upgrade prettier to 1.0.0! (prettier#65)

This adds support for the new `semi` and `useTabs` options!