Bump version to 0.5 and update release process docs.

- make note of ovm-build tarball dependencies, and clang dependency
- benchmarks/id.sh: a minor test function fix.

INSTALL.txt

@@ -12,8 +12,8 @@ Quick Start

If you haven't already done so, extract the tarball:
 
    tar -x --xz < oil-0.5.alpha4.tar.xz
    cd oil-0.5.alpha4
    tar -x --xz < oil-0.5.tar.xz
    cd oil-0.5

Either install as /usr/local/bin/osh:

@@ -31,7 +31,7 @@ The latter doesn't require root access, but it requires ~/bin to be in your
PATH.

NOTE: Out-of-tree builds are NOT currently supported, so you have to be in the
oil-0.5.alpha4 directory.
oil-0.5 directory.

Smoke Test
----------

benchmarks/id.sh

@@ -254,7 +254,7 @@ dump-compiler-id() {
}

test-compiler-id() {
  dump-compiler-id gcc
  dump-compiler-id $(which gcc)
  dump-compiler-id $CLANG
  head _tmp/compiler-id/*/version.txt
}

doc/osh-quick-ref-toc.txt

@@ -2,7 +2,7 @@ OSH Quick Reference

- Below is a list of topics, organized into [Sections].
- The X prefix means "unimplemented".  Oil features are all unimplemented!
- HTML version: https://www.oilshell.org/release/0.5.alpha4/doc/osh-quick-ref.html
- HTML version: https://www.oilshell.org/release/0.5/doc/osh-quick-ref.html

INTRO
  [Overview]      overview   osh-vs-oil   command-vs-expr

doc/release-index.md

@@ -1,6 +1,6 @@
<!-- NOTE: This file is at /release/$VERSION/index.html -->

Oil Version 0.5.alpha4
Oil Version 0.5
-----------------

### What's New

oil-version.txt

@@ -1,4 +1,4 @@
0.5.alpha4
0.5

# The first line of this file is the Oil version, and the rest is ignored.
# It's used at build time for the release tarball, and at runtime for oil 

scripts/release.sh

@@ -12,7 +12,10 @@
#     Sync up oilshell/benchmark-data repo.
#     flanders: $0 benchmark-build, then $0 benchmark-run
#     - for stability, restart flanders
#     - prereq: benchmarks/osh-runtime.sh {download,extract}
#     - prereqs:
#       - benchmarks/osh-runtime.sh {download,extract}
#       - benchmarks/ovm-build.sh {download,extract-oil,extract-other}
#       - build/codegen.sh {download,extract}-clang (for OVM build benchmarks)
#     lisa: $0 benchmark-run, then $0 benchmark-run-on-1-machine (oheap)
#     Commit files to oilshell/benchmark-data repo and sync.
#   benchmarks/report.sh all