Implement separate linking on gdc

Fix output flags for compilers != dmd

Add "singleFile" as a possible --build-mode value on the help screen.

Fix UpgradeOptions.printUpgradesOnly. Fixes #323. ...

This commit disables fetching upgrade candidates and prints a message for each upgradeable dependency instead.

Fix using an invalid configuration in DependencyResolver when validating dependencies. ...

This was caused by the fix for #359.

Add an explanation message for exit code -9. ...

This is a common enough issue to warrant a little diagnostic assistance (the compiler/linker process getting KILLed by the kernel due to out-of-memory).

Add a warning for dependency specifications that mismatch the version selections. Fixes #333.

Only upgrade branch dependencies when an explicit upgrade is requested.

Force upgrade of branch based dependencies. Fixes #360.

Fix DependencyResolver's unit test.

Fix optional dependencies being always downloaded with the new dependency resolver. Fixes #359.

Output a reason when implicitly fetching packages.

Create a .gitignore file for "dub init". See #364.

Merge pull request #364 from Geod24/singlefile ...

Add --build-mode=singleFile switch. Fixes #17.

Added singleFile support

Added .gitignore

Merge pull request #362 from sinkuu/smallfix ...

Trivial small fixes

Remove redundant try-catch

Fix helpText

Make prepareBuildSettings, extractBuildOptions and setTarget const

Use executeShell() to invoke the compiler. See #356. ...

execute() doesn't support running scripts with shebang lines. Still needs to be actually tested with a script on Linux/OS X.

Revert "Fix detection of the "command" command line argument. Fixes #351." ...

This reverts commit cab8ca5.

Fix detection of the "command" command line argument. Fixes #351.

Resolve sub packages when loading path based dependencies. Fixes #347.

Add a --temp-build switch to force building in the TEMP folder. Fixes #294.

Avoid assertion when building path based sub packages (or packages with path based dependencies).

Avoid downloading base package for non-existent sub package references, if possible. ...

When it can be proven that a certain sub package doesn't exist (this is the case when the base package descriptions doesn't contain any path based dependencies), the dependency will be skipped as invalid instead of downloading the whole package to search for the sub package there.

Only add platform flags for targets that generate an actual binary. Fixes #346.

Avoid downloading base packages if possible. Fixes #345. ...

Before manually extracting a sub package from a base package, the package description of the base package is first searched for the sub package. This avoids the otherwise necessary download of the base package whenever the sub package is a non-path-based one. This also opens the way for the dub registry to always collect all sub packages into the reported package description, so that it will never be necessary to actually download a package for getting a sub package.

Fix detection of root package references during dependency resolution. See #334. ...

- References to and from sub packages of the root package are now also recognized as coming from the root package
 - Any dependency reference within a certain package "family"* (including path based ones) is now mapped to the same base package (circumventing the lookup of all possible matches)

* "family" == base package and all of its sub packages