Change common libs for XCode/apple (RIPD-305):

Removes unnecessary common link libs related to openssl, which we link
to explicitly using finder vars now. THis allows the generated XCode
project to link without error. Tested with CMake 3.9.0 and XCode 8.3.3.

.travis.yml

@@ -79,3 +79,5 @@ notifications:
   irc:
     channels:
       - "chat.freenode.net#ripple-dev"
+
+dist: precise

Builds/CMake/CMakeFuncs.cmake

@@ -748,7 +748,7 @@ macro(link_common_libraries cur_project)
       find_library(app_kit AppKit)
       find_library(foundation Foundation)
       target_link_libraries(${cur_project}
-        crypto ssl ${app_kit} ${foundation})
+        ${app_kit} ${foundation})
     else()
       target_link_libraries(${cur_project} rt)
     endif()

Builds/XCode/README.md

@@ -2,13 +2,13 @@
 
 ## Important
 
-We don't recommend OS X for rippled production use at this time. Currently, the
+We don't recommend macos for rippled production use at this time. Currently, the
 Ubuntu platform has received the highest level of quality assurance and
-testing.
+testing. That said, macos is suitable for many development/test tasks.
 
 ## Prerequisites
 
-You'll need OSX 10.8 or later
+You'll need macos 10.8 or later
 
 To clone the source code repository, create branches for inspection or
 modification, build rippled using clang, and run the system tests you will need
@@ -17,7 +17,7 @@ these software components:
 * [XCode](https://developer.apple.com/xcode/)
 * [Homebrew](http://brew.sh/)
 * [Git](http://git-scm.com/)
-* [Scons](http://www.scons.org/)
+* [CMake](http://cmake.org/)
 
 ## Install Software
 
@@ -64,14 +64,14 @@ later.
 
 ### Install Scons
 
-Requires version 2.3.0 or later
+Requires version 3.6.0 or later
 
 ```
-brew install scons
+brew install cmake
 ```
 
 `brew` will generally install the latest stable version of any package, which
-will satisfy the scons minimum version requirement for rippled.
+should satisfy the cmake minimum version requirement for rippled.
 
 ### Install Package Config
 
@@ -163,10 +163,16 @@ export BOOST_ROOT=/Users/Abigail/Downloads/boost_1_61_0
 ## Build
 
 ```
-scons
+mkdir xcode_build && cd xcode_build
+cmake -GXcode ..
 ```
 
-See: [here](https://ripple.com/wiki/Rippled_build_instructions#Building)
+There are a number of variables/options that our CMake files support and they
+can be added to the above command as needed (e.g. `-Dassert=ON` to enable
+asserts)
+
+After generation succeeds, the xcode project file can be opened and used to
+build and debug.
 
 ## Unit Tests (Recommended)