Merge pull request#405 from streamich/swtich-parserSwtich parser

chore(release): 1.6.0 [skip ci]# [1.6.0](v1.5.0...v1.6.0) (2019-03-03)### Features* 🎸 add findRoot() function ([d75bc86](d75bc86))* 🎸 set `depth` attribute in mdastToFlat() ([0f5eca7](0f5eca7))

chore(release): 1.5.0 [skip ci]# [1.5.0](v1.4.0...v1.5.0) (2019-03-03)### Features* 🎸 add `parent` key to all nodes ([c4d611f](c4d611f))

chore(release): 1.4.0 [skip ci]# [1.4.0](v1.3.0...v1.4.0) (2019-03-01)### Features* 🎸 merge footnote definitions in replace() call ([f552d43](f552d43))

chore(release): 1.3.0 [skip ci]# [1.3.0](v1.2.0...v1.3.0) (2019-02-27)### Features* 🎸 add `cnt` field to all footnotes to track their order ([61b0788](61b0788))

chore(release): 1.2.0 [skip ci]# [1.2.0](v1.1.0...v1.2.0) (2019-02-27)### Features* 🎸 add footnoteOrder list ([b743a48](b743a48))* 🎸 implement footnoteOrder list ([89209c5](89209c5))

chore(release): 1.1.0 [skip ci]# [1.1.0](v1.0.0...v1.1.0) (2019-02-25)### Features* 🎸 add idx key ([b8c00c9](b8c00c9))* 🎸 add replace() function ([76c78ac](76c78ac))

chore(release): 1.0.0 [skip ci]# 1.0.0 (2019-02-25)### Features* 🎸 add flatToMdast() function ([939317c](939317c))* 🎸 add mdastToFlat function ([c120131](c120131))