Adds information on operator precedence

Adds a order of operations table and a note for Matlab users.
update NEWS
add text/html writemime for MethodList and Method (fix #4952)
hopefully more robust way of getting github URL (don't assume module name is Pkg name)
silence compiler warning
Fix #5217
minor update of hypot to ensure consistency of output types
Merge pull request #5219 from lindahua/dh/hypottypes

minor update of hypot to ensure consistency of output types
only show ccall literal address warning in imaging mode. closes #5215
Merge pull request #5202 from mbauman/doc-precedence

Doc: Add information on operator precedence
Merge branch 'master' of github.com:JuliaLang/julia
fix doc for && and || and update helpdb
annotate the types of arguments for derived trigonometric & hyperbolic functions
Merge pull request #5220 from lindahua/dh/trigono2

Annotate arguments for derived trigonometric & hyperbolic functions
fix off-by-1 in isqrt. closes #4884
Merge branch 'master' of github.com:JuliaLang/julia
Merge pull request #4991 from stevengj/methodshow

add text/html writemime for MethodList and Method (fix #4952)