Add in USE_SYSTEM_LIBUV

Adds in makefile macros for LIBUV resources to allow for a nonexistant deps/libuv folder
Adds libuv-dev package installation in Travis
Change to julia-specific libuv package naming
More updates to front section of manual

[x] Fixes typos, minor formatting and grammar issues and uses check marks
[x] Better cross-referencing
[x] Adds explanation of how primitive numeric types map onto machine arithmetic (#2085)
Merge pull request #2881 from staticfloat/usesystemlibuv

Add in USE_SYSTEM_LIBUV
Yet more refactoring of manual

- Adds new section on naming variables and style convention
- Refactors linear algebra content out of Arrays
- Turn more lists of functions into tables
- Documents built-in Exceptions, symbol(), isnan, isinf, isfinite, info, warn
- Updates list of vectorized functions and documents @vectorize_?args macros
- Turns embedded HTML footnotes into ReST footnotes
- Fixes sectioning issue in Arrays
- More cross-referencing, especially for non-standard string literals
- Minor grammatical, language, spelling cleanup
- Remove user-specific output from sample Julia snippets
make keys() and values() return view objects. closes #2347
contains() should now be used for all is-element-of checking
has(d,k), for now, just does contains(keys(d),k), but is likely
to be removed or renamed haskey()
Fix broken table in manual
note that exceptions are a slow way to compute sqrt
other minor fixes to that doc section
Use the mutated factor or matrix object as the return value

In mutating functions return the mutated factor or matrix object so
the value can be used as an argument to other function calls.
pkg2 wip: use more custom types.
Adds LaTeX commands to render Chinese, Korean and check marks correctly
Updated cfunction in base.rst

Added documentation to specify return type annotations in cfunction
Merge pull request #2887 from amitmurthy/patch-1

Updated cfunction in base.rst
WINDOWS: fix normalization of BUILD_OS variable
improve complex sin and cos. fixes #2889
Merge branch 'master' of github.com:JuliaLang/julia
Fixes tan for small values of argument (followup to #2889)
improve complex tan, sinh, cosh, tanh
fixes #2889
attempt fix of #2893
Generalize set_dash to support offsets