Add scripts and instructions for Linux builds.

This is mostly based on @bensku work.

See https://github.com/PhilippC/keepass2android/pull/156

src/build-scripts/build-all.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+set -e
+
+echo '*****************************************'
+echo '********** Building Java parts **********'
+echo '*****************************************'
+./build-java.sh
+
+echo '*****************************************'
+echo '******** Building Xamarin parts *********'
+echo '*****************************************'
+./build-xamarin.sh
+
+echo '*****************************************'
+echo '************** Building APK *************'
+echo '*****************************************'
+./build-apk.sh
+
+echo
+echo 'Congratulations! You you can find the target APK in src/keepass2android/bin/Debug/.'

src/build-scripts/build-apk.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+set -e
+
+pushd ../keepass2android
+
+xabuild keepass2android.csproj /t:SignAndroidPackage "$@"
+
+popd

src/build-scripts/build-java.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+set -e
+
+pushd ../java/
+
+pushd JavaFileStorageTest-AS
+./gradlew assemble
+popd
+
+pushd KP2ASoftkeyboard_AS
+./gradlew assemble
+popd
+
+pushd Keepass2AndroidPluginSDK2
+./gradlew assemble
+popd
+
+popd

src/build-scripts/build-xamarin.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+set -e
+
+pushd ..
+
+pushd Kp2aBusinessLogic/Io
+
+if [ -f "DropboxFileStorageKeys.cs" ]
+then
+  echo "DropboxFileStorageKeys.cs found."
+else
+  cp DropboxFileStorageKeysDummy.cs DropboxFileStorageKeys.cs
+fi
+
+popd
+
+pushd keepass2android
+./UseManifestDebug.sh
+popd
+
+# call "C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\vcvarsall.bat" x86_amd64
+
+xabuild KeePass.sln /target:keepass2android /p:BuildProjectReferences=true /p:Configuration="Debug" /p:Platform="Any CPU" "$@"
+
+popd