Travis CI: Specify node.js 5.6 since 5.7.0 has regressions.
Travis CI: Specify node.js 5.6 since 5.7.0 has regressions.

This should be reverted when the next 5.x version is out.

[skip sauce]

SweetProcess/bootstrap,Hightrack/bootstrap,kvlsrg/bootstrap,tjkohli/bootstrap,tomlutzenberger/bootstrap,realcrowd/bootstrap,lemuelbarango/bootstrap,sealocal/bootstrap,edanbarak/bootstrap,johnajacob/bootstrap,JumpLinkNetwork/bootstrap-backward,bardiharborow/bootstrap,seanwu99/bootstrap,igoynawamreh/bootstrap,tibo66/bootstrap,johnajacob/bootstrap,seanwu99/bootstrap,copperdesign/bootstrap,seanwu99/bootstrap,tibo66/bootstrap,davethegr8/bootstrap,inway/bootstrap,bardiharborow/bootstrap,SweetProcess/bootstrap,stanwmusic/bootstrap,m5o/bootstrap,GerHobbelt/bootstrap,realcrowd/bootstrap,GerHobbelt/bootstrap,abvalentine/bootstrap,tibo66/bootstrap,zalog/bootstrap,creativewebjp/bootstrap,frostbitten/bootstrap,Hightrack/bootstrap,GerHobbelt/bootstrap,gijsbotje/bootstrap,afuno/bootstrap,wesamco/bootstrap-rtl,edanbarak/bootstrap,igoynawamreh/bootstrap,yuyokk/bootstrap,fschumann1211/bootstrap,n054/bootstrap,bootstrapbrasil/bootstrap,tomlutzenberger/bootstrap,vsn4ik/bootstrap,frostbitten/bootstrap,afuno/bootstrap,lipis/bootstrap,peterblazejewicz/bootstrap,Hemphill/bootstrap-docs,Lyricalz/bootstrap,janseliger/bootstrap,bootstrapbrasil/bootstrap,david-schopf/bootstrap,Hemphill/bootstrap-docs,SweetProcess/bootstrap,edanbarak/bootstrap,abvalentine/bootstrap,copperdesign/bootstrap,copperdesign/bootstrap,hebbet/bootstrap,lipis/bootstrap,bardiharborow/bootstrap,slavanga/bootstrap,seanwu99/bootstrap,twbs/bootstrap,janseliger/bootstrap,andresgalante/bootstrap,davethegr8/bootstrap,zalog/bootstrap,NCARB/bootstrap,tomlutzenberger/bootstrap,andresgalante/bootstrap,NCARB/bootstrap,igoynawamreh/bootstrap,twbs/bootstrap,Delagen/bootstrap,Scoutski/bootstrap,gijsbotje/bootstrap,supergibbs/bootstrap,JumpLinkNetwork/bootstrap-backward,9-chirno/chirno,frostbitten/bootstrap,sealocal/bootstrap,stanwmusic/bootstrap,tjkohli/bootstrap,lemuelbarango/bootstrap,tibo66/bootstrap,fschumann1211/bootstrap,JumpLinkNetwork/bootstrap-backward,Hightrack/bootstrap,yuyokk/bootstrap,supergibbs/bootstrap,zalog/bootstrap,edanbarak/bootstrap,tagliala/bootstrap,n054/bootstrap,tagliala/bootstrap,johnajacob/bootstrap,supergibbs/bootstrap,nice-fungal/bootstrap,TheFridayInstitute/bootstrap,wesamco/bootstrap-rtl,coliff/bootstrap,davethegr8/bootstrap,jipexu/bootstrap,Scoutski/bootstrap,vsn4ik/bootstrap,n054/bootstrap,nice-fungal/bootstrap,lemuelbarango/bootstrap,sealocal/bootstrap,Lyricalz/bootstrap,yuyokk/bootstrap,inway/bootstrap,lemuelbarango/bootstrap,gijsbotje/bootstrap,davethegr8/bootstrap,9-chirno/chirno,Hemphill/bootstrap-docs,sealocal/bootstrap,slavanga/bootstrap,m5o/bootstrap,andresgalante/bootstrap,kvlsrg/bootstrap,xt0rted/bootstrap,johnajacob/bootstrap,afuno/bootstrap,inway/bootstrap,joblocal/bootstrap,jipexu/bootstrap,lipis/bootstrap,jipexu/bootstrap,kvlsrg/bootstrap,abvalentine/bootstrap,tagliala/bootstrap,NCARB/bootstrap,Delagen/bootstrap,stanwmusic/bootstrap,david-schopf/bootstrap,frostbitten/bootstrap,bootstrapbrasil/bootstrap,creativewebjp/bootstrap,yuyokk/bootstrap,stanwmusic/bootstrap,igoynawamreh/bootstrap,abvalentine/bootstrap,IdanCo/bootstrap,NCARB/bootstrap,n054/bootstrap,TheFridayInstitute/bootstrap,Lyricalz/bootstrap,copperdesign/bootstrap,vsn4ik/bootstrap,janseliger/bootstrap,TheFridayInstitute/bootstrap,Scoutski/bootstrap,xt0rted/bootstrap,jipexu/bootstrap,wesamco/bootstrap-rtl,Scoutski/bootstrap,andresgalante/bootstrap,peterblazejewicz/bootstrap,Hemphill/bootstrap-docs,joblocal/bootstrap,realcrowd/bootstrap,creativewebjp/bootstrap,joblocal/bootstrap,slavanga/bootstrap,janseliger/bootstrap,realcrowd/bootstrap,supergibbs/bootstrap,Delagen/bootstrap,coliff/bootstrap,bardiharborow/bootstrap,hebbet/bootstrap,peterblazejewicz/bootstrap,hebbet/bootstrap,wesamco/bootstrap-rtl,TheFridayInstitute/bootstrap,IdanCo/bootstrap,hebbet/bootstrap,xt0rted/bootstrap,slavanga/bootstrap,nice-fungal/bootstrap,SweetProcess/bootstrap,creativewebjp/bootstrap,lipis/bootstrap,9-chirno/chirno,Lyricalz/bootstrap,david-schopf/bootstrap,Delagen/bootstrap,afuno/bootstrap,xt0rted/bootstrap,gijsbotje/bootstrap,vsn4ik/bootstrap,9-chirno/chirno,JumpLinkNetwork/bootstrap-backward,fschumann1211/bootstrap,fschumann1211/bootstrap,joblocal/bootstrap,IdanCo/bootstrap,IdanCo/bootstrap