Change linux images on travis

Remove deprecated PPAs and switch to distros that provide the compilers we want

Author: fgo-ableton

.travis.yml

@@ -2,7 +2,6 @@
 
 language: cpp
 sudo: required
-dist: trusty
 branches:
   only:
     - master
@@ -38,6 +37,7 @@ matrix:
 
     # Linux with Clang 3.6, 64-bit Debug, Alsa
     - os: linux
+      dist: trusty
       compiler: clang
       addons:
         apt:
@@ -47,36 +47,27 @@ matrix:
 
     # Linux with Clang 3.6, 64-bit Release, Jack
     - os: linux
+      dist: trusty
       compiler: clang
       addons:
         apt:
-          sources: ['llvm-toolchain-precise-3.8', 'ubuntu-toolchain-r-test']
+          sources: ['ubuntu-toolchain-r-test']
           packages: ['clang-3.8', 'g++-5', 'valgrind', 'portaudio19-dev']
       env: COMPILER=clang++-3.8 WORDSIZE=64 CONFIGURATION=Release AUDIO=Jack
 
     # Linux with Clang 5.0, 64-bit Debug, Alsa
     - os: linux
+      dist: bionic
       compiler: clang
       addons:
         apt:
-          sources: ['llvm-toolchain-trusty-5.0', 'ubuntu-toolchain-r-test']
+          sources: ['ubuntu-toolchain-r-test']
           packages: ['clang-5.0', 'g++-5', 'valgrind', 'portaudio19-dev']
       env: COMPILER=clang++-5.0 WORDSIZE=64 CONFIGURATION=Debug AUDIO=Alsa
 
-    # Linux with GCC 5.x, 32-bit Release
-#    - os: linux
-#      compiler: gcc
-#      addons:
-#        apt:
-#          sources: ['ubuntu-toolchain-r-test']
-#          packages: ['g++-5', 'g++-5-multilib', 'linux-libc-dev:i386', 'valgrind:i386',
-#                     'libxext-dev:i386', 'libglapi-mesa:i386',
-#                     'libgl1-mesa-glx:i386', 'libgl1-mesa-dev:i386',
-#                     'portaudio19-dev:i386', 'libglib2.0-0:i386']
-#      env: COMPILER=g++-5 WORDSIZE=32 CONFIGURATION=Release
-
     # Linux with GCC 5.x, 64-bit Release, Alsa
     - os: linux
+      dist: bionic
       compiler: gcc
       addons:
         apt:
@@ -86,6 +77,7 @@ matrix:
 
     # Linux with GCC 6.x, 64-bit Release, Alsa
     - os: linux
+      dist: bionic
       compiler: gcc
       addons:
         apt:
@@ -95,6 +87,7 @@ matrix:
 
     # ESP32
     - os: linux
+      dist: bionic
       compiler: clang
       addons:
         apt:
@@ -104,6 +97,7 @@ matrix:
 
     # Code formatting verification
     - os: linux
+      dist: bionic
       compiler: clang
       env: CONFIGURATION=Formatting LLVM_VERSION=6.0
       services: