gradle-plugin, readme: Use relative links

GRADLE_PLUGIN.md

@@ -50,7 +50,7 @@ details). The plugin uses `src/main/kotlin/` as a default directory for sources.
 ## Using C interop
 
 Kotlin/Native provides an easy interaction with native C libraries. The detailed description of this mechanism
-can be found in [`INTEROP.md`](https://github.com/JetBrains/kotlin-native/blob/master/INTEROP.md) while this section
+can be found in [`INTEROP.md`](INTEROP.md) while this section
 describes how to use Gradle to build Kotlin/Native apps using C libraries.
 
 All the C libraies used should be defined in `konanInterop` block.
@@ -62,16 +62,15 @@ All the C libraies used should be defined in `konanInterop` block.
     }
     
 Each element (interop) in this block corresponds to some native library described by a def-file (see
-[`INTEROP.md`](https://github.com/JetBrains/kotlin-native/blob/master/INTEROP.md) to read more about def-files). The
-default path to the def-file of an interop is `src/main/c_interop/<interop-name>.def`.
+[`INTEROP.md`](INTEROP.md) to read more about def-files). The default path to the def-file of an interop is
+`src/main/c_interop/<interop-name>.def`.
 
 Each interop is processed by the plugin in two steps:
 
 1. Stub generation. In this step the plugin uses `cinterop` tool to generate Kotlin and bitcode (*.bc) stubs for the
 library. You can specify additional parameters for this tool in the interop block (e.g. a custom def-file is specified
 in the example above). See [**Plugin DSL**](#plugin-dsl) section below for available parameters and
-[`INTEROP.md`](https://github.com/JetBrains/kotlin-native/blob/master/INTEROP.md) for `cinterop` tool
-description.
+[`INTEROP.md`](INTEROP.md) for `cinterop` tool description.
 2. Stub compilation. In this step the plugin uses Kotlin/Native compiler to compile the stubs generated by the step (1)
 into a klib which can be linked with a Kotlin/Native application.
 
@@ -97,6 +96,7 @@ You also can use an interop from another project:
 ### Tasks
 
 The Kotlin/Native plugin creates the following tasks:
+
 * __compileKonan*ArtifactName*__. The plugin creates such a task for each an artifact defined in a `konanArtifacts` block.
 You may get this task using the `compilationTask` property of an artifact or by its name:
 
@@ -250,7 +250,7 @@ For this project the task graph will be the following:
      konanInterop {
          interopName {
              defFile project.file("deffile.def")                    // Def-file for stub generation.
-             pkg 'org.sample'                                       // Package to place the stubs generated.
+             pkg 'org.sample'                                       // Package to place stubs generated.
              target 'macbook'                                       // Target platform.
 
              // Options to be passed to compiler and linker by cinterop tool.